dotemacs

sqlite3.h (515857B)

---

 /*
 ** 2001-09-15
 **
 ** The author disclaims copyright to this source code.  In place of
 ** a legal notice, here is a blessing:
 **
 **    May you do good and not evil.
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 ** This header file defines the interface that the SQLite library
 ** presents to client programs.  If a C-function, structure, datatype,
 ** or constant definition does not appear in this file, then it is
 ** not a published API of SQLite, is subject to change without
 ** notice, and should not be referenced by programs that use SQLite.
 **
 ** Some of the definitions that are in this file are marked as
 ** "experimental".  Experimental interfaces are normally new
 ** features recently added to SQLite.  We do not anticipate changes
 ** to experimental interfaces but reserve the right to make minor changes
 ** if experience from use "in the wild" suggest such changes are prudent.
 **
 ** The official C-language API documentation for SQLite is derived
 ** from comments in this file.  This file is the authoritative source
 ** on how SQLite interfaces are supposed to operate.
 **
 ** The name of this file under configuration management is "sqlite.h.in".
 ** The makefile makes some minor changes to this file (such as inserting
 ** the version number) and changes its name to "sqlite3.h" as
 ** part of the build process.
 */
 #ifndef SQLITE3_H
 #define SQLITE3_H
 #include <stdarg.h>     /* Needed for the definition of va_list */
 
 /*
 ** Make sure we can call this stuff from C++.
 */
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 
 /*
 ** Provide the ability to override linkage features of the interface.
 */
 #ifndef SQLITE_EXTERN
 # define SQLITE_EXTERN extern
 #endif
 #ifndef SQLITE_API
 # define SQLITE_API
 #endif
 #ifndef SQLITE_CDECL
 # define SQLITE_CDECL
 #endif
 #ifndef SQLITE_APICALL
 # define SQLITE_APICALL
 #endif
 #ifndef SQLITE_STDCALL
 # define SQLITE_STDCALL SQLITE_APICALL
 #endif
 #ifndef SQLITE_CALLBACK
 # define SQLITE_CALLBACK
 #endif
 #ifndef SQLITE_SYSAPI
 # define SQLITE_SYSAPI
 #endif
 
 /*
 ** These no-op macros are used in front of interfaces to mark those
 ** interfaces as either deprecated or experimental.  New applications
 ** should not use deprecated interfaces - they are supported for backwards
 ** compatibility only.  Application writers should be aware that
 ** experimental interfaces are subject to change in point releases.
 **
 ** These macros used to resolve to various kinds of compiler magic that
 ** would generate warning messages when they were used.  But that
 ** compiler magic ended up generating such a flurry of bug reports
 ** that we have taken it all out and gone back to using simple
 ** noop macros.
 */
 #define SQLITE_DEPRECATED
 #define SQLITE_EXPERIMENTAL
 
 /*
 ** Ensure these symbols were not defined by some previous header file.
 */
 #ifdef SQLITE_VERSION
 # undef SQLITE_VERSION
 #endif
 #ifdef SQLITE_VERSION_NUMBER
 # undef SQLITE_VERSION_NUMBER
 #endif
 
 /*
 ** CAPI3REF: Compile-Time Library Version Numbers
 **
 ** ^(The [SQLITE_VERSION] C preprocessor macro in the sqlite3.h header
 ** evaluates to a string literal that is the SQLite version in the
 ** format "X.Y.Z" where X is the major version number (always 3 for
 ** SQLite3) and Y is the minor version number and Z is the release number.)^
 ** ^(The [SQLITE_VERSION_NUMBER] C preprocessor macro resolves to an integer
 ** with the value (X*1000000 + Y*1000 + Z) where X, Y, and Z are the same
 ** numbers used in [SQLITE_VERSION].)^
 ** The SQLITE_VERSION_NUMBER for any given release of SQLite will also
 ** be larger than the release from which it is derived.  Either Y will
 ** be held constant and Z will be incremented or else Y will be incremented
 ** and Z will be reset to zero.
 **
 ** Since [version 3.6.18] ([dateof:3.6.18]), 
 ** SQLite source code has been stored in the
 ** <a href="http://www.fossil-scm.org/">Fossil configuration management
 ** system</a>.  ^The SQLITE_SOURCE_ID macro evaluates to
 ** a string which identifies a particular check-in of SQLite
 ** within its configuration management system.  ^The SQLITE_SOURCE_ID
 ** string contains the date and time of the check-in (UTC) and a SHA1
 ** or SHA3-256 hash of the entire source tree.  If the source code has
 ** been edited in any way since it was last checked in, then the last
 ** four hexadecimal digits of the hash may be modified.
 **
 ** See also: [sqlite3_libversion()],
 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],
 ** [sqlite_version()] and [sqlite_source_id()].
 */
 #define SQLITE_VERSION        "3.22.0"
 #define SQLITE_VERSION_NUMBER 3022000
 #define SQLITE_SOURCE_ID      "2018-01-22 18:45:57 0c55d179733b46d8d0ba4d88e01a25e10677046ee3da1d5b1581e86726f2171d"
 
 /*
 ** CAPI3REF: Run-Time Library Version Numbers
 ** KEYWORDS: sqlite3_version sqlite3_sourceid
 **
 ** These interfaces provide the same information as the [SQLITE_VERSION],
 ** [SQLITE_VERSION_NUMBER], and [SQLITE_SOURCE_ID] C preprocessor macros
 ** but are associated with the library instead of the header file.  ^(Cautious
 ** programmers might include assert() statements in their application to
 ** verify that values returned by these interfaces match the macros in
 ** the header, and thus ensure that the application is
 ** compiled with matching library and header files.
 **
 ** <blockquote><pre>
 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );
 ** assert( strncmp(sqlite3_sourceid(),SQLITE_SOURCE_ID,80)==0 );
 ** assert( strcmp(sqlite3_libversion(),SQLITE_VERSION)==0 );
 ** </pre></blockquote>)^
 **
 ** ^The sqlite3_version[] string constant contains the text of [SQLITE_VERSION]
 ** macro.  ^The sqlite3_libversion() function returns a pointer to the
 ** to the sqlite3_version[] string constant.  The sqlite3_libversion()
 ** function is provided for use in DLLs since DLL users usually do not have
 ** direct access to string constants within the DLL.  ^The
 ** sqlite3_libversion_number() function returns an integer equal to
 ** [SQLITE_VERSION_NUMBER].  ^(The sqlite3_sourceid() function returns 
 ** a pointer to a string constant whose value is the same as the 
 ** [SQLITE_SOURCE_ID] C preprocessor macro.  Except if SQLite is built
 ** using an edited copy of [the amalgamation], then the last four characters
 ** of the hash might be different from [SQLITE_SOURCE_ID].)^
 **
 ** See also: [sqlite_version()] and [sqlite_source_id()].
 */
 SQLITE_API SQLITE_EXTERN const char sqlite3_version[];
 SQLITE_API const char *sqlite3_libversion(void);
 SQLITE_API const char *sqlite3_sourceid(void);
 SQLITE_API int sqlite3_libversion_number(void);
 
 /*
 ** CAPI3REF: Run-Time Library Compilation Options Diagnostics
 **
 ** ^The sqlite3_compileoption_used() function returns 0 or 1 
 ** indicating whether the specified option was defined at 
 ** compile time.  ^The SQLITE_ prefix may be omitted from the 
 ** option name passed to sqlite3_compileoption_used().  
 **
 ** ^The sqlite3_compileoption_get() function allows iterating
 ** over the list of options that were defined at compile time by
 ** returning the N-th compile time option string.  ^If N is out of range,
 ** sqlite3_compileoption_get() returns a NULL pointer.  ^The SQLITE_ 
 ** prefix is omitted from any strings returned by 
 ** sqlite3_compileoption_get().
 **
 ** ^Support for the diagnostic functions sqlite3_compileoption_used()
 ** and sqlite3_compileoption_get() may be omitted by specifying the 
 ** [SQLITE_OMIT_COMPILEOPTION_DIAGS] option at compile time.
 **
 ** See also: SQL functions [sqlite_compileoption_used()] and
 ** [sqlite_compileoption_get()] and the [compile_options pragma].
 */
 #ifndef SQLITE_OMIT_COMPILEOPTION_DIAGS
 SQLITE_API int sqlite3_compileoption_used(const char *zOptName);
 SQLITE_API const char *sqlite3_compileoption_get(int N);
 #endif
 
 /*
 ** CAPI3REF: Test To See If The Library Is Threadsafe
 **
 ** ^The sqlite3_threadsafe() function returns zero if and only if
 ** SQLite was compiled with mutexing code omitted due to the
 ** [SQLITE_THREADSAFE] compile-time option being set to 0.
 **
 ** SQLite can be compiled with or without mutexes.  When
 ** the [SQLITE_THREADSAFE] C preprocessor macro is 1 or 2, mutexes
 ** are enabled and SQLite is threadsafe.  When the
 ** [SQLITE_THREADSAFE] macro is 0, 
 ** the mutexes are omitted.  Without the mutexes, it is not safe
 ** to use SQLite concurrently from more than one thread.
 **
 ** Enabling mutexes incurs a measurable performance penalty.
 ** So if speed is of utmost importance, it makes sense to disable
 ** the mutexes.  But for maximum safety, mutexes should be enabled.
 ** ^The default behavior is for mutexes to be enabled.
 **
 ** This interface can be used by an application to make sure that the
 ** version of SQLite that it is linking against was compiled with
 ** the desired setting of the [SQLITE_THREADSAFE] macro.
 **
 ** This interface only reports on the compile-time mutex setting
 ** of the [SQLITE_THREADSAFE] flag.  If SQLite is compiled with
 ** SQLITE_THREADSAFE=1 or =2 then mutexes are enabled by default but
 ** can be fully or partially disabled using a call to [sqlite3_config()]
 ** with the verbs [SQLITE_CONFIG_SINGLETHREAD], [SQLITE_CONFIG_MULTITHREAD],
 ** or [SQLITE_CONFIG_SERIALIZED].  ^(The return value of the
 ** sqlite3_threadsafe() function shows only the compile-time setting of
 ** thread safety, not any run-time changes to that setting made by
 ** sqlite3_config(). In other words, the return value from sqlite3_threadsafe()
 ** is unchanged by calls to sqlite3_config().)^
 **
 ** See the [threading mode] documentation for additional information.
 */
 SQLITE_API int sqlite3_threadsafe(void);
 
 /*
 ** CAPI3REF: Database Connection Handle
 ** KEYWORDS: {database connection} {database connections}
 **
 ** Each open SQLite database is represented by a pointer to an instance of
 ** the opaque structure named "sqlite3".  It is useful to think of an sqlite3
 ** pointer as an object.  The [sqlite3_open()], [sqlite3_open16()], and
 ** [sqlite3_open_v2()] interfaces are its constructors, and [sqlite3_close()]
 ** and [sqlite3_close_v2()] are its destructors.  There are many other
 ** interfaces (such as
 ** [sqlite3_prepare_v2()], [sqlite3_create_function()], and
 ** [sqlite3_busy_timeout()] to name but three) that are methods on an
 ** sqlite3 object.
 */
 typedef struct sqlite3 sqlite3;
 
 /*
 ** CAPI3REF: 64-Bit Integer Types
 ** KEYWORDS: sqlite_int64 sqlite_uint64
 **
 ** Because there is no cross-platform way to specify 64-bit integer types
 ** SQLite includes typedefs for 64-bit signed and unsigned integers.
 **
 ** The sqlite3_int64 and sqlite3_uint64 are the preferred type definitions.
 ** The sqlite_int64 and sqlite_uint64 types are supported for backwards
 ** compatibility only.
 **
 ** ^The sqlite3_int64 and sqlite_int64 types can store integer values
 ** between -9223372036854775808 and +9223372036854775807 inclusive.  ^The
 ** sqlite3_uint64 and sqlite_uint64 types can store integer values 
 ** between 0 and +18446744073709551615 inclusive.
 */
 #ifdef SQLITE_INT64_TYPE
   typedef SQLITE_INT64_TYPE sqlite_int64;
 # ifdef SQLITE_UINT64_TYPE
     typedef SQLITE_UINT64_TYPE sqlite_uint64;
 # else  
     typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;
 # endif
 #elif defined(_MSC_VER) || defined(__BORLANDC__)
   typedef __int64 sqlite_int64;
   typedef unsigned __int64 sqlite_uint64;
 #else
   typedef long long int sqlite_int64;
   typedef unsigned long long int sqlite_uint64;
 #endif
 typedef sqlite_int64 sqlite3_int64;
 typedef sqlite_uint64 sqlite3_uint64;
 
 /*
 ** If compiling for a processor that lacks floating point support,
 ** substitute integer for floating-point.
 */
 #ifdef SQLITE_OMIT_FLOATING_POINT
 # define double sqlite3_int64
 #endif
 
 /*
 ** CAPI3REF: Closing A Database Connection
 ** DESTRUCTOR: sqlite3
 **
 ** ^The sqlite3_close() and sqlite3_close_v2() routines are destructors
 ** for the [sqlite3] object.
 ** ^Calls to sqlite3_close() and sqlite3_close_v2() return [SQLITE_OK] if
 ** the [sqlite3] object is successfully destroyed and all associated
 ** resources are deallocated.
 **
 ** ^If the database connection is associated with unfinalized prepared
 ** statements or unfinished sqlite3_backup objects then sqlite3_close()
 ** will leave the database connection open and return [SQLITE_BUSY].
 ** ^If sqlite3_close_v2() is called with unfinalized prepared statements
 ** and/or unfinished sqlite3_backups, then the database connection becomes
 ** an unusable "zombie" which will automatically be deallocated when the
 ** last prepared statement is finalized or the last sqlite3_backup is
 ** finished.  The sqlite3_close_v2() interface is intended for use with
 ** host languages that are garbage collected, and where the order in which
 ** destructors are called is arbitrary.
 **
 ** Applications should [sqlite3_finalize | finalize] all [prepared statements],
 ** [sqlite3_blob_close | close] all [BLOB handles], and 
 ** [sqlite3_backup_finish | finish] all [sqlite3_backup] objects associated
 ** with the [sqlite3] object prior to attempting to close the object.  ^If
 ** sqlite3_close_v2() is called on a [database connection] that still has
 ** outstanding [prepared statements], [BLOB handles], and/or
 ** [sqlite3_backup] objects then it returns [SQLITE_OK] and the deallocation
 ** of resources is deferred until all [prepared statements], [BLOB handles],
 ** and [sqlite3_backup] objects are also destroyed.
 **
 ** ^If an [sqlite3] object is destroyed while a transaction is open,
 ** the transaction is automatically rolled back.
 **
 ** The C parameter to [sqlite3_close(C)] and [sqlite3_close_v2(C)]
 ** must be either a NULL
 ** pointer or an [sqlite3] object pointer obtained
 ** from [sqlite3_open()], [sqlite3_open16()], or
 ** [sqlite3_open_v2()], and not previously closed.
 ** ^Calling sqlite3_close() or sqlite3_close_v2() with a NULL pointer
 ** argument is a harmless no-op.
 */
 SQLITE_API int sqlite3_close(sqlite3*);
 SQLITE_API int sqlite3_close_v2(sqlite3*);
 
 /*
 ** The type for a callback function.
 ** This is legacy and deprecated.  It is included for historical
 ** compatibility and is not documented.
 */
 typedef int (*sqlite3_callback)(void*,int,char**, char**);
 
 /*
 ** CAPI3REF: One-Step Query Execution Interface
 ** METHOD: sqlite3
 **
 ** The sqlite3_exec() interface is a convenience wrapper around
 ** [sqlite3_prepare_v2()], [sqlite3_step()], and [sqlite3_finalize()],
 ** that allows an application to run multiple statements of SQL
 ** without having to use a lot of C code. 
 **
 ** ^The sqlite3_exec() interface runs zero or more UTF-8 encoded,
 ** semicolon-separate SQL statements passed into its 2nd argument,
 ** in the context of the [database connection] passed in as its 1st
 ** argument.  ^If the callback function of the 3rd argument to
 ** sqlite3_exec() is not NULL, then it is invoked for each result row
 ** coming out of the evaluated SQL statements.  ^The 4th argument to
 ** sqlite3_exec() is relayed through to the 1st argument of each
 ** callback invocation.  ^If the callback pointer to sqlite3_exec()
 ** is NULL, then no callback is ever invoked and result rows are
 ** ignored.
 **
 ** ^If an error occurs while evaluating the SQL statements passed into
 ** sqlite3_exec(), then execution of the current statement stops and
 ** subsequent statements are skipped.  ^If the 5th parameter to sqlite3_exec()
 ** is not NULL then any error message is written into memory obtained
 ** from [sqlite3_malloc()] and passed back through the 5th parameter.
 ** To avoid memory leaks, the application should invoke [sqlite3_free()]
 ** on error message strings returned through the 5th parameter of
 ** sqlite3_exec() after the error message string is no longer needed.
 ** ^If the 5th parameter to sqlite3_exec() is not NULL and no errors
 ** occur, then sqlite3_exec() sets the pointer in its 5th parameter to
 ** NULL before returning.
 **
 ** ^If an sqlite3_exec() callback returns non-zero, the sqlite3_exec()
 ** routine returns SQLITE_ABORT without invoking the callback again and
 ** without running any subsequent SQL statements.
 **
 ** ^The 2nd argument to the sqlite3_exec() callback function is the
 ** number of columns in the result.  ^The 3rd argument to the sqlite3_exec()
 ** callback is an array of pointers to strings obtained as if from
 ** [sqlite3_column_text()], one for each column.  ^If an element of a
 ** result row is NULL then the corresponding string pointer for the
 ** sqlite3_exec() callback is a NULL pointer.  ^The 4th argument to the
 ** sqlite3_exec() callback is an array of pointers to strings where each
 ** entry represents the name of corresponding result column as obtained
 ** from [sqlite3_column_name()].
 **
 ** ^If the 2nd parameter to sqlite3_exec() is a NULL pointer, a pointer
 ** to an empty string, or a pointer that contains only whitespace and/or 
 ** SQL comments, then no SQL statements are evaluated and the database
 ** is not changed.
 **
 ** Restrictions:
 **
 ** <ul>
 ** <li> The application must ensure that the 1st parameter to sqlite3_exec()
 **      is a valid and open [database connection].
 ** <li> The application must not close the [database connection] specified by
 **      the 1st parameter to sqlite3_exec() while sqlite3_exec() is running.
 ** <li> The application must not modify the SQL statement text passed into
 **      the 2nd parameter of sqlite3_exec() while sqlite3_exec() is running.
 ** </ul>
 */
 SQLITE_API int sqlite3_exec(
   sqlite3*,                                  /* An open database */
   const char *sql,                           /* SQL to be evaluated */
   int (*callback)(void*,int,char**,char**),  /* Callback function */
   void *,                                    /* 1st argument to callback */
   char **errmsg                              /* Error msg written here */
 );
 
 /*
 ** CAPI3REF: Result Codes
 ** KEYWORDS: {result code definitions}
 **
 ** Many SQLite functions return an integer result code from the set shown
 ** here in order to indicate success or failure.
 **
 ** New error codes may be added in future versions of SQLite.
 **
 ** See also: [extended result code definitions]
 */
 #define SQLITE_OK           0   /* Successful result */
 /* beginning-of-error-codes */
 #define SQLITE_ERROR        1   /* Generic error */
 #define SQLITE_INTERNAL     2   /* Internal logic error in SQLite */
 #define SQLITE_PERM         3   /* Access permission denied */
 #define SQLITE_ABORT        4   /* Callback routine requested an abort */
 #define SQLITE_BUSY         5   /* The database file is locked */
 #define SQLITE_LOCKED       6   /* A table in the database is locked */
 #define SQLITE_NOMEM        7   /* A malloc() failed */
 #define SQLITE_READONLY     8   /* Attempt to write a readonly database */
 #define SQLITE_INTERRUPT    9   /* Operation terminated by sqlite3_interrupt()*/
 #define SQLITE_IOERR       10   /* Some kind of disk I/O error occurred */
 #define SQLITE_CORRUPT     11   /* The database disk image is malformed */
 #define SQLITE_NOTFOUND    12   /* Unknown opcode in sqlite3_file_control() */
 #define SQLITE_FULL        13   /* Insertion failed because database is full */
 #define SQLITE_CANTOPEN    14   /* Unable to open the database file */
 #define SQLITE_PROTOCOL    15   /* Database lock protocol error */
 #define SQLITE_EMPTY       16   /* Internal use only */
 #define SQLITE_SCHEMA      17   /* The database schema changed */
 #define SQLITE_TOOBIG      18   /* String or BLOB exceeds size limit */
 #define SQLITE_CONSTRAINT  19   /* Abort due to constraint violation */
 #define SQLITE_MISMATCH    20   /* Data type mismatch */
 #define SQLITE_MISUSE      21   /* Library used incorrectly */
 #define SQLITE_NOLFS       22   /* Uses OS features not supported on host */
 #define SQLITE_AUTH        23   /* Authorization denied */
 #define SQLITE_FORMAT      24   /* Not used */
 #define SQLITE_RANGE       25   /* 2nd parameter to sqlite3_bind out of range */
 #define SQLITE_NOTADB      26   /* File opened that is not a database file */
 #define SQLITE_NOTICE      27   /* Notifications from sqlite3_log() */
 #define SQLITE_WARNING     28   /* Warnings from sqlite3_log() */
 #define SQLITE_ROW         100  /* sqlite3_step() has another row ready */
 #define SQLITE_DONE        101  /* sqlite3_step() has finished executing */
 /* end-of-error-codes */
 
 /*
 ** CAPI3REF: Extended Result Codes
 ** KEYWORDS: {extended result code definitions}
 **
 ** In its default configuration, SQLite API routines return one of 30 integer
 ** [result codes].  However, experience has shown that many of
 ** these result codes are too coarse-grained.  They do not provide as
 ** much information about problems as programmers might like.  In an effort to
 ** address this, newer versions of SQLite (version 3.3.8 [dateof:3.3.8]
 ** and later) include
 ** support for additional result codes that provide more detailed information
 ** about errors. These [extended result codes] are enabled or disabled
 ** on a per database connection basis using the
 ** [sqlite3_extended_result_codes()] API.  Or, the extended code for
 ** the most recent error can be obtained using
 ** [sqlite3_extended_errcode()].
 */
 #define SQLITE_ERROR_MISSING_COLLSEQ   (SQLITE_ERROR | (1<<8))
 #define SQLITE_ERROR_RETRY             (SQLITE_ERROR | (2<<8))
 #define SQLITE_IOERR_READ              (SQLITE_IOERR | (1<<8))
 #define SQLITE_IOERR_SHORT_READ        (SQLITE_IOERR | (2<<8))
 #define SQLITE_IOERR_WRITE             (SQLITE_IOERR | (3<<8))
 #define SQLITE_IOERR_FSYNC             (SQLITE_IOERR | (4<<8))
 #define SQLITE_IOERR_DIR_FSYNC         (SQLITE_IOERR | (5<<8))
 #define SQLITE_IOERR_TRUNCATE          (SQLITE_IOERR | (6<<8))
 #define SQLITE_IOERR_FSTAT             (SQLITE_IOERR | (7<<8))
 #define SQLITE_IOERR_UNLOCK            (SQLITE_IOERR | (8<<8))
 #define SQLITE_IOERR_RDLOCK            (SQLITE_IOERR | (9<<8))
 #define SQLITE_IOERR_DELETE            (SQLITE_IOERR | (10<<8))
 #define SQLITE_IOERR_BLOCKED           (SQLITE_IOERR | (11<<8))
 #define SQLITE_IOERR_NOMEM             (SQLITE_IOERR | (12<<8))
 #define SQLITE_IOERR_ACCESS            (SQLITE_IOERR | (13<<8))
 #define SQLITE_IOERR_CHECKRESERVEDLOCK (SQLITE_IOERR | (14<<8))
 #define SQLITE_IOERR_LOCK              (SQLITE_IOERR | (15<<8))
 #define SQLITE_IOERR_CLOSE             (SQLITE_IOERR | (16<<8))
 #define SQLITE_IOERR_DIR_CLOSE         (SQLITE_IOERR | (17<<8))
 #define SQLITE_IOERR_SHMOPEN           (SQLITE_IOERR | (18<<8))
 #define SQLITE_IOERR_SHMSIZE           (SQLITE_IOERR | (19<<8))
 #define SQLITE_IOERR_SHMLOCK           (SQLITE_IOERR | (20<<8))
 #define SQLITE_IOERR_SHMMAP            (SQLITE_IOERR | (21<<8))
 #define SQLITE_IOERR_SEEK              (SQLITE_IOERR | (22<<8))
 #define SQLITE_IOERR_DELETE_NOENT      (SQLITE_IOERR | (23<<8))
 #define SQLITE_IOERR_MMAP              (SQLITE_IOERR | (24<<8))
 #define SQLITE_IOERR_GETTEMPPATH       (SQLITE_IOERR | (25<<8))
 #define SQLITE_IOERR_CONVPATH          (SQLITE_IOERR | (26<<8))
 #define SQLITE_IOERR_VNODE             (SQLITE_IOERR | (27<<8))
 #define SQLITE_IOERR_AUTH              (SQLITE_IOERR | (28<<8))
 #define SQLITE_IOERR_BEGIN_ATOMIC      (SQLITE_IOERR | (29<<8))
 #define SQLITE_IOERR_COMMIT_ATOMIC     (SQLITE_IOERR | (30<<8))
 #define SQLITE_IOERR_ROLLBACK_ATOMIC   (SQLITE_IOERR | (31<<8))
 #define SQLITE_LOCKED_SHAREDCACHE      (SQLITE_LOCKED |  (1<<8))
 #define SQLITE_BUSY_RECOVERY           (SQLITE_BUSY   |  (1<<8))
 #define SQLITE_BUSY_SNAPSHOT           (SQLITE_BUSY   |  (2<<8))
 #define SQLITE_CANTOPEN_NOTEMPDIR      (SQLITE_CANTOPEN | (1<<8))
 #define SQLITE_CANTOPEN_ISDIR          (SQLITE_CANTOPEN | (2<<8))
 #define SQLITE_CANTOPEN_FULLPATH       (SQLITE_CANTOPEN | (3<<8))
 #define SQLITE_CANTOPEN_CONVPATH       (SQLITE_CANTOPEN | (4<<8))
 #define SQLITE_CORRUPT_VTAB            (SQLITE_CORRUPT | (1<<8))
 #define SQLITE_READONLY_RECOVERY       (SQLITE_READONLY | (1<<8))
 #define SQLITE_READONLY_CANTLOCK       (SQLITE_READONLY | (2<<8))
 #define SQLITE_READONLY_ROLLBACK       (SQLITE_READONLY | (3<<8))
 #define SQLITE_READONLY_DBMOVED        (SQLITE_READONLY | (4<<8))
 #define SQLITE_READONLY_CANTINIT       (SQLITE_READONLY | (5<<8))
 #define SQLITE_READONLY_DIRECTORY      (SQLITE_READONLY | (6<<8))
 #define SQLITE_ABORT_ROLLBACK          (SQLITE_ABORT | (2<<8))
 #define SQLITE_CONSTRAINT_CHECK        (SQLITE_CONSTRAINT | (1<<8))
 #define SQLITE_CONSTRAINT_COMMITHOOK   (SQLITE_CONSTRAINT | (2<<8))
 #define SQLITE_CONSTRAINT_FOREIGNKEY   (SQLITE_CONSTRAINT | (3<<8))
 #define SQLITE_CONSTRAINT_FUNCTION     (SQLITE_CONSTRAINT | (4<<8))
 #define SQLITE_CONSTRAINT_NOTNULL      (SQLITE_CONSTRAINT | (5<<8))
 #define SQLITE_CONSTRAINT_PRIMARYKEY   (SQLITE_CONSTRAINT | (6<<8))
 #define SQLITE_CONSTRAINT_TRIGGER      (SQLITE_CONSTRAINT | (7<<8))
 #define SQLITE_CONSTRAINT_UNIQUE       (SQLITE_CONSTRAINT | (8<<8))
 #define SQLITE_CONSTRAINT_VTAB         (SQLITE_CONSTRAINT | (9<<8))
 #define SQLITE_CONSTRAINT_ROWID        (SQLITE_CONSTRAINT |(10<<8))
 #define SQLITE_NOTICE_RECOVER_WAL      (SQLITE_NOTICE | (1<<8))
 #define SQLITE_NOTICE_RECOVER_ROLLBACK (SQLITE_NOTICE | (2<<8))
 #define SQLITE_WARNING_AUTOINDEX       (SQLITE_WARNING | (1<<8))
 #define SQLITE_AUTH_USER               (SQLITE_AUTH | (1<<8))
 #define SQLITE_OK_LOAD_PERMANENTLY     (SQLITE_OK | (1<<8))
 
 /*
 ** CAPI3REF: Flags For File Open Operations
 **
 ** These bit values are intended for use in the
 ** 3rd parameter to the [sqlite3_open_v2()] interface and
 ** in the 4th parameter to the [sqlite3_vfs.xOpen] method.
 */
 #define SQLITE_OPEN_READONLY         0x00000001  /* Ok for sqlite3_open_v2() */
 #define SQLITE_OPEN_READWRITE        0x00000002  /* Ok for sqlite3_open_v2() */
 #define SQLITE_OPEN_CREATE           0x00000004  /* Ok for sqlite3_open_v2() */
 #define SQLITE_OPEN_DELETEONCLOSE    0x00000008  /* VFS only */
 #define SQLITE_OPEN_EXCLUSIVE        0x00000010  /* VFS only */
 #define SQLITE_OPEN_AUTOPROXY        0x00000020  /* VFS only */
 #define SQLITE_OPEN_URI              0x00000040  /* Ok for sqlite3_open_v2() */
 #define SQLITE_OPEN_MEMORY           0x00000080  /* Ok for sqlite3_open_v2() */
 #define SQLITE_OPEN_MAIN_DB          0x00000100  /* VFS only */
 #define SQLITE_OPEN_TEMP_DB          0x00000200  /* VFS only */
 #define SQLITE_OPEN_TRANSIENT_DB     0x00000400  /* VFS only */
 #define SQLITE_OPEN_MAIN_JOURNAL     0x00000800  /* VFS only */
 #define SQLITE_OPEN_TEMP_JOURNAL     0x00001000  /* VFS only */
 #define SQLITE_OPEN_SUBJOURNAL       0x00002000  /* VFS only */
 #define SQLITE_OPEN_MASTER_JOURNAL   0x00004000  /* VFS only */
 #define SQLITE_OPEN_NOMUTEX          0x00008000  /* Ok for sqlite3_open_v2() */
 #define SQLITE_OPEN_FULLMUTEX        0x00010000  /* Ok for sqlite3_open_v2() */
 #define SQLITE_OPEN_SHAREDCACHE      0x00020000  /* Ok for sqlite3_open_v2() */
 #define SQLITE_OPEN_PRIVATECACHE     0x00040000  /* Ok for sqlite3_open_v2() */
 #define SQLITE_OPEN_WAL              0x00080000  /* VFS only */
 
 /* Reserved:                         0x00F00000 */
 
 /*
 ** CAPI3REF: Device Characteristics
 **
 ** The xDeviceCharacteristics method of the [sqlite3_io_methods]
 ** object returns an integer which is a vector of these
 ** bit values expressing I/O characteristics of the mass storage
 ** device that holds the file that the [sqlite3_io_methods]
 ** refers to.
 **
 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
 ** mean that writes of blocks that are nnn bytes in size and
 ** are aligned to an address which is an integer multiple of
 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
 ** that when data is appended to a file, the data is appended
 ** first then the size of the file is extended, never the other
 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
 ** information is written to disk in the same order as calls
 ** to xWrite().  The SQLITE_IOCAP_POWERSAFE_OVERWRITE property means that
 ** after reboot following a crash or power loss, the only bytes in a
 ** file that were written at the application level might have changed
 ** and that adjacent bytes, even bytes within the same sector are
 ** guaranteed to be unchanged.  The SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN
 ** flag indicates that a file cannot be deleted when open.  The
 ** SQLITE_IOCAP_IMMUTABLE flag indicates that the file is on
 ** read-only media and cannot be changed even by processes with
 ** elevated privileges.
 **
 ** The SQLITE_IOCAP_BATCH_ATOMIC property means that the underlying
 ** filesystem supports doing multiple write operations atomically when those
 ** write operations are bracketed by [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] and
 ** [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].
 */
 #define SQLITE_IOCAP_ATOMIC                 0x00000001
 #define SQLITE_IOCAP_ATOMIC512              0x00000002
 #define SQLITE_IOCAP_ATOMIC1K               0x00000004
 #define SQLITE_IOCAP_ATOMIC2K               0x00000008
 #define SQLITE_IOCAP_ATOMIC4K               0x00000010
 #define SQLITE_IOCAP_ATOMIC8K               0x00000020
 #define SQLITE_IOCAP_ATOMIC16K              0x00000040
 #define SQLITE_IOCAP_ATOMIC32K              0x00000080
 #define SQLITE_IOCAP_ATOMIC64K              0x00000100
 #define SQLITE_IOCAP_SAFE_APPEND            0x00000200
 #define SQLITE_IOCAP_SEQUENTIAL             0x00000400
 #define SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN  0x00000800
 #define SQLITE_IOCAP_POWERSAFE_OVERWRITE    0x00001000
 #define SQLITE_IOCAP_IMMUTABLE              0x00002000
 #define SQLITE_IOCAP_BATCH_ATOMIC           0x00004000
 
 /*
 ** CAPI3REF: File Locking Levels
 **
 ** SQLite uses one of these integer values as the second
 ** argument to calls it makes to the xLock() and xUnlock() methods
 ** of an [sqlite3_io_methods] object.
 */
 #define SQLITE_LOCK_NONE          0
 #define SQLITE_LOCK_SHARED        1
 #define SQLITE_LOCK_RESERVED      2
 #define SQLITE_LOCK_PENDING       3
 #define SQLITE_LOCK_EXCLUSIVE     4
 
 /*
 ** CAPI3REF: Synchronization Type Flags
 **
 ** When SQLite invokes the xSync() method of an
 ** [sqlite3_io_methods] object it uses a combination of
 ** these integer values as the second argument.
 **
 ** When the SQLITE_SYNC_DATAONLY flag is used, it means that the
 ** sync operation only needs to flush data to mass storage.  Inode
 ** information need not be flushed. If the lower four bits of the flag
 ** equal SQLITE_SYNC_NORMAL, that means to use normal fsync() semantics.
 ** If the lower four bits equal SQLITE_SYNC_FULL, that means
 ** to use Mac OS X style fullsync instead of fsync().
 **
 ** Do not confuse the SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags
 ** with the [PRAGMA synchronous]=NORMAL and [PRAGMA synchronous]=FULL
 ** settings.  The [synchronous pragma] determines when calls to the
 ** xSync VFS method occur and applies uniformly across all platforms.
 ** The SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL flags determine how
 ** energetic or rigorous or forceful the sync operations are and
 ** only make a difference on Mac OSX for the default SQLite code.
 ** (Third-party VFS implementations might also make the distinction
 ** between SQLITE_SYNC_NORMAL and SQLITE_SYNC_FULL, but among the
 ** operating systems natively supported by SQLite, only Mac OSX
 ** cares about the difference.)
 */
 #define SQLITE_SYNC_NORMAL        0x00002
 #define SQLITE_SYNC_FULL          0x00003
 #define SQLITE_SYNC_DATAONLY      0x00010
 
 /*
 ** CAPI3REF: OS Interface Open File Handle
 **
 ** An [sqlite3_file] object represents an open file in the 
 ** [sqlite3_vfs | OS interface layer].  Individual OS interface
 ** implementations will
 ** want to subclass this object by appending additional fields
 ** for their own use.  The pMethods entry is a pointer to an
 ** [sqlite3_io_methods] object that defines methods for performing
 ** I/O operations on the open file.
 */
 typedef struct sqlite3_file sqlite3_file;
 struct sqlite3_file {
   const struct sqlite3_io_methods *pMethods;  /* Methods for an open file */
 };
 
 /*
 ** CAPI3REF: OS Interface File Virtual Methods Object
 **
 ** Every file opened by the [sqlite3_vfs.xOpen] method populates an
 ** [sqlite3_file] object (or, more commonly, a subclass of the
 ** [sqlite3_file] object) with a pointer to an instance of this object.
 ** This object defines the methods used to perform various operations
 ** against the open file represented by the [sqlite3_file] object.
 **
 ** If the [sqlite3_vfs.xOpen] method sets the sqlite3_file.pMethods element 
 ** to a non-NULL pointer, then the sqlite3_io_methods.xClose method
 ** may be invoked even if the [sqlite3_vfs.xOpen] reported that it failed.  The
 ** only way to prevent a call to xClose following a failed [sqlite3_vfs.xOpen]
 ** is for the [sqlite3_vfs.xOpen] to set the sqlite3_file.pMethods element
 ** to NULL.
 **
 ** The flags argument to xSync may be one of [SQLITE_SYNC_NORMAL] or
 ** [SQLITE_SYNC_FULL].  The first choice is the normal fsync().
 ** The second choice is a Mac OS X style fullsync.  The [SQLITE_SYNC_DATAONLY]
 ** flag may be ORed in to indicate that only the data of the file
 ** and not its inode needs to be synced.
 **
 ** The integer values to xLock() and xUnlock() are one of
 ** <ul>
 ** <li> [SQLITE_LOCK_NONE],
 ** <li> [SQLITE_LOCK_SHARED],
 ** <li> [SQLITE_LOCK_RESERVED],
 ** <li> [SQLITE_LOCK_PENDING], or
 ** <li> [SQLITE_LOCK_EXCLUSIVE].
 ** </ul>
 ** xLock() increases the lock. xUnlock() decreases the lock.
 ** The xCheckReservedLock() method checks whether any database connection,
 ** either in this process or in some other process, is holding a RESERVED,
 ** PENDING, or EXCLUSIVE lock on the file.  It returns true
 ** if such a lock exists and false otherwise.
 **
 ** The xFileControl() method is a generic interface that allows custom
 ** VFS implementations to directly control an open file using the
 ** [sqlite3_file_control()] interface.  The second "op" argument is an
 ** integer opcode.  The third argument is a generic pointer intended to
 ** point to a structure that may contain arguments or space in which to
 ** write return values.  Potential uses for xFileControl() might be
 ** functions to enable blocking locks with timeouts, to change the
 ** locking strategy (for example to use dot-file locks), to inquire
 ** about the status of a lock, or to break stale locks.  The SQLite
 ** core reserves all opcodes less than 100 for its own use.
 ** A [file control opcodes | list of opcodes] less than 100 is available.
 ** Applications that define a custom xFileControl method should use opcodes
 ** greater than 100 to avoid conflicts.  VFS implementations should
 ** return [SQLITE_NOTFOUND] for file control opcodes that they do not
 ** recognize.
 **
 ** The xSectorSize() method returns the sector size of the
 ** device that underlies the file.  The sector size is the
 ** minimum write that can be performed without disturbing
 ** other bytes in the file.  The xDeviceCharacteristics()
 ** method returns a bit vector describing behaviors of the
 ** underlying device:
 **
 ** <ul>
 ** <li> [SQLITE_IOCAP_ATOMIC]
 ** <li> [SQLITE_IOCAP_ATOMIC512]
 ** <li> [SQLITE_IOCAP_ATOMIC1K]
 ** <li> [SQLITE_IOCAP_ATOMIC2K]
 ** <li> [SQLITE_IOCAP_ATOMIC4K]
 ** <li> [SQLITE_IOCAP_ATOMIC8K]
 ** <li> [SQLITE_IOCAP_ATOMIC16K]
 ** <li> [SQLITE_IOCAP_ATOMIC32K]
 ** <li> [SQLITE_IOCAP_ATOMIC64K]
 ** <li> [SQLITE_IOCAP_SAFE_APPEND]
 ** <li> [SQLITE_IOCAP_SEQUENTIAL]
 ** <li> [SQLITE_IOCAP_UNDELETABLE_WHEN_OPEN]
 ** <li> [SQLITE_IOCAP_POWERSAFE_OVERWRITE]
 ** <li> [SQLITE_IOCAP_IMMUTABLE]
 ** <li> [SQLITE_IOCAP_BATCH_ATOMIC]
 ** </ul>
 **
 ** The SQLITE_IOCAP_ATOMIC property means that all writes of
 ** any size are atomic.  The SQLITE_IOCAP_ATOMICnnn values
 ** mean that writes of blocks that are nnn bytes in size and
 ** are aligned to an address which is an integer multiple of
 ** nnn are atomic.  The SQLITE_IOCAP_SAFE_APPEND value means
 ** that when data is appended to a file, the data is appended
 ** first then the size of the file is extended, never the other
 ** way around.  The SQLITE_IOCAP_SEQUENTIAL property means that
 ** information is written to disk in the same order as calls
 ** to xWrite().
 **
 ** If xRead() returns SQLITE_IOERR_SHORT_READ it must also fill
 ** in the unread portions of the buffer with zeros.  A VFS that
 ** fails to zero-fill short reads might seem to work.  However,
 ** failure to zero-fill short reads will eventually lead to
 ** database corruption.
 */
 typedef struct sqlite3_io_methods sqlite3_io_methods;
 struct sqlite3_io_methods {
   int iVersion;
   int (*xClose)(sqlite3_file*);
   int (*xRead)(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
   int (*xWrite)(sqlite3_file*, const void*, int iAmt, sqlite3_int64 iOfst);
   int (*xTruncate)(sqlite3_file*, sqlite3_int64 size);
   int (*xSync)(sqlite3_file*, int flags);
   int (*xFileSize)(sqlite3_file*, sqlite3_int64 *pSize);
   int (*xLock)(sqlite3_file*, int);
   int (*xUnlock)(sqlite3_file*, int);
   int (*xCheckReservedLock)(sqlite3_file*, int *pResOut);
   int (*xFileControl)(sqlite3_file*, int op, void *pArg);
   int (*xSectorSize)(sqlite3_file*);
   int (*xDeviceCharacteristics)(sqlite3_file*);
   /* Methods above are valid for version 1 */
   int (*xShmMap)(sqlite3_file*, int iPg, int pgsz, int, void volatile**);
   int (*xShmLock)(sqlite3_file*, int offset, int n, int flags);
   void (*xShmBarrier)(sqlite3_file*);
   int (*xShmUnmap)(sqlite3_file*, int deleteFlag);
   /* Methods above are valid for version 2 */
   int (*xFetch)(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp);
   int (*xUnfetch)(sqlite3_file*, sqlite3_int64 iOfst, void *p);
   /* Methods above are valid for version 3 */
   /* Additional methods may be added in future releases */
 };
 
 /*
 ** CAPI3REF: Standard File Control Opcodes
 ** KEYWORDS: {file control opcodes} {file control opcode}
 **
 ** These integer constants are opcodes for the xFileControl method
 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]
 ** interface.
 **
 ** <ul>
 ** <li>[[SQLITE_FCNTL_LOCKSTATE]]
 ** The [SQLITE_FCNTL_LOCKSTATE] opcode is used for debugging.  This
 ** opcode causes the xFileControl method to write the current state of
 ** the lock (one of [SQLITE_LOCK_NONE], [SQLITE_LOCK_SHARED],
 ** [SQLITE_LOCK_RESERVED], [SQLITE_LOCK_PENDING], or [SQLITE_LOCK_EXCLUSIVE])
 ** into an integer that the pArg argument points to. This capability
 ** is used during testing and is only available when the SQLITE_TEST
 ** compile-time option is used.
 **
 ** <li>[[SQLITE_FCNTL_SIZE_HINT]]
 ** The [SQLITE_FCNTL_SIZE_HINT] opcode is used by SQLite to give the VFS
 ** layer a hint of how large the database file will grow to be during the
 ** current transaction.  This hint is not guaranteed to be accurate but it
 ** is often close.  The underlying VFS might choose to preallocate database
 ** file space based on this hint in order to help writes to the database
 ** file run faster.
 **
 ** <li>[[SQLITE_FCNTL_CHUNK_SIZE]]
 ** The [SQLITE_FCNTL_CHUNK_SIZE] opcode is used to request that the VFS
 ** extends and truncates the database file in chunks of a size specified
 ** by the user. The fourth argument to [sqlite3_file_control()] should 
 ** point to an integer (type int) containing the new chunk-size to use
 ** for the nominated database. Allocating database file space in large
 ** chunks (say 1MB at a time), may reduce file-system fragmentation and
 ** improve performance on some systems.
 **
 ** <li>[[SQLITE_FCNTL_FILE_POINTER]]
 ** The [SQLITE_FCNTL_FILE_POINTER] opcode is used to obtain a pointer
 ** to the [sqlite3_file] object associated with a particular database
 ** connection.  See also [SQLITE_FCNTL_JOURNAL_POINTER].
 **
 ** <li>[[SQLITE_FCNTL_JOURNAL_POINTER]]
 ** The [SQLITE_FCNTL_JOURNAL_POINTER] opcode is used to obtain a pointer
 ** to the [sqlite3_file] object associated with the journal file (either
 ** the [rollback journal] or the [write-ahead log]) for a particular database
 ** connection.  See also [SQLITE_FCNTL_FILE_POINTER].
 **
 ** <li>[[SQLITE_FCNTL_SYNC_OMITTED]]
 ** No longer in use.
 **
 ** <li>[[SQLITE_FCNTL_SYNC]]
 ** The [SQLITE_FCNTL_SYNC] opcode is generated internally by SQLite and
 ** sent to the VFS immediately before the xSync method is invoked on a
 ** database file descriptor. Or, if the xSync method is not invoked 
 ** because the user has configured SQLite with 
 ** [PRAGMA synchronous | PRAGMA synchronous=OFF] it is invoked in place 
 ** of the xSync method. In most cases, the pointer argument passed with
 ** this file-control is NULL. However, if the database file is being synced
 ** as part of a multi-database commit, the argument points to a nul-terminated
 ** string containing the transactions master-journal file name. VFSes that 
 ** do not need this signal should silently ignore this opcode. Applications 
 ** should not call [sqlite3_file_control()] with this opcode as doing so may 
 ** disrupt the operation of the specialized VFSes that do require it.  
 **
 ** <li>[[SQLITE_FCNTL_COMMIT_PHASETWO]]
 ** The [SQLITE_FCNTL_COMMIT_PHASETWO] opcode is generated internally by SQLite
 ** and sent to the VFS after a transaction has been committed immediately
 ** but before the database is unlocked. VFSes that do not need this signal
 ** should silently ignore this opcode. Applications should not call
 ** [sqlite3_file_control()] with this opcode as doing so may disrupt the 
 ** operation of the specialized VFSes that do require it.  
 **
 ** <li>[[SQLITE_FCNTL_WIN32_AV_RETRY]]
 ** ^The [SQLITE_FCNTL_WIN32_AV_RETRY] opcode is used to configure automatic
 ** retry counts and intervals for certain disk I/O operations for the
 ** windows [VFS] in order to provide robustness in the presence of
 ** anti-virus programs.  By default, the windows VFS will retry file read,
 ** file write, and file delete operations up to 10 times, with a delay
 ** of 25 milliseconds before the first retry and with the delay increasing
 ** by an additional 25 milliseconds with each subsequent retry.  This
 ** opcode allows these two values (10 retries and 25 milliseconds of delay)
 ** to be adjusted.  The values are changed for all database connections
 ** within the same process.  The argument is a pointer to an array of two
 ** integers where the first integer is the new retry count and the second
 ** integer is the delay.  If either integer is negative, then the setting
 ** is not changed but instead the prior value of that setting is written
 ** into the array entry, allowing the current retry settings to be
 ** interrogated.  The zDbName parameter is ignored.
 **
 ** <li>[[SQLITE_FCNTL_PERSIST_WAL]]
 ** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
 ** persistent [WAL | Write Ahead Log] setting.  By default, the auxiliary
 ** write ahead log and shared memory files used for transaction control
 ** are automatically deleted when the latest connection to the database
 ** closes.  Setting persistent WAL mode causes those files to persist after
 ** close.  Persisting the files is useful when other processes that do not
 ** have write permission on the directory containing the database file want
 ** to read the database file, as the WAL and shared memory files must exist
 ** in order for the database to be readable.  The fourth parameter to
 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
 ** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
 ** WAL mode.  If the integer is -1, then it is overwritten with the current
 ** WAL persistence setting.
 **
 ** <li>[[SQLITE_FCNTL_POWERSAFE_OVERWRITE]]
 ** ^The [SQLITE_FCNTL_POWERSAFE_OVERWRITE] opcode is used to set or query the
 ** persistent "powersafe-overwrite" or "PSOW" setting.  The PSOW setting
 ** determines the [SQLITE_IOCAP_POWERSAFE_OVERWRITE] bit of the
 ** xDeviceCharacteristics methods. The fourth parameter to
 ** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
 ** That integer is 0 to disable zero-damage mode or 1 to enable zero-damage
 ** mode.  If the integer is -1, then it is overwritten with the current
 ** zero-damage mode setting.
 **
 ** <li>[[SQLITE_FCNTL_OVERWRITE]]
 ** ^The [SQLITE_FCNTL_OVERWRITE] opcode is invoked by SQLite after opening
 ** a write transaction to indicate that, unless it is rolled back for some
 ** reason, the entire database file will be overwritten by the current 
 ** transaction. This is used by VACUUM operations.
 **
 ** <li>[[SQLITE_FCNTL_VFSNAME]]
 ** ^The [SQLITE_FCNTL_VFSNAME] opcode can be used to obtain the names of
 ** all [VFSes] in the VFS stack.  The names are of all VFS shims and the
 ** final bottom-level VFS are written into memory obtained from 
 ** [sqlite3_malloc()] and the result is stored in the char* variable
 ** that the fourth parameter of [sqlite3_file_control()] points to.
 ** The caller is responsible for freeing the memory when done.  As with
 ** all file-control actions, there is no guarantee that this will actually
 ** do anything.  Callers should initialize the char* variable to a NULL
 ** pointer in case this file-control is not implemented.  This file-control
 ** is intended for diagnostic use only.
 **
 ** <li>[[SQLITE_FCNTL_VFS_POINTER]]
 ** ^The [SQLITE_FCNTL_VFS_POINTER] opcode finds a pointer to the top-level
 ** [VFSes] currently in use.  ^(The argument X in
 ** sqlite3_file_control(db,SQLITE_FCNTL_VFS_POINTER,X) must be
 ** of type "[sqlite3_vfs] **".  This opcodes will set *X
 ** to a pointer to the top-level VFS.)^
 ** ^When there are multiple VFS shims in the stack, this opcode finds the
 ** upper-most shim only.
 **
 ** <li>[[SQLITE_FCNTL_PRAGMA]]
 ** ^Whenever a [PRAGMA] statement is parsed, an [SQLITE_FCNTL_PRAGMA] 
 ** file control is sent to the open [sqlite3_file] object corresponding
 ** to the database file to which the pragma statement refers. ^The argument
 ** to the [SQLITE_FCNTL_PRAGMA] file control is an array of
 ** pointers to strings (char**) in which the second element of the array
 ** is the name of the pragma and the third element is the argument to the
 ** pragma or NULL if the pragma has no argument.  ^The handler for an
 ** [SQLITE_FCNTL_PRAGMA] file control can optionally make the first element
 ** of the char** argument point to a string obtained from [sqlite3_mprintf()]
 ** or the equivalent and that string will become the result of the pragma or
 ** the error message if the pragma fails. ^If the
 ** [SQLITE_FCNTL_PRAGMA] file control returns [SQLITE_NOTFOUND], then normal 
 ** [PRAGMA] processing continues.  ^If the [SQLITE_FCNTL_PRAGMA]
 ** file control returns [SQLITE_OK], then the parser assumes that the
 ** VFS has handled the PRAGMA itself and the parser generates a no-op
 ** prepared statement if result string is NULL, or that returns a copy
 ** of the result string if the string is non-NULL.
 ** ^If the [SQLITE_FCNTL_PRAGMA] file control returns
 ** any result code other than [SQLITE_OK] or [SQLITE_NOTFOUND], that means
 ** that the VFS encountered an error while handling the [PRAGMA] and the
 ** compilation of the PRAGMA fails with an error.  ^The [SQLITE_FCNTL_PRAGMA]
 ** file control occurs at the beginning of pragma statement analysis and so
 ** it is able to override built-in [PRAGMA] statements.
 **
 ** <li>[[SQLITE_FCNTL_BUSYHANDLER]]
 ** ^The [SQLITE_FCNTL_BUSYHANDLER]
 ** file-control may be invoked by SQLite on the database file handle
 ** shortly after it is opened in order to provide a custom VFS with access
 ** to the connections busy-handler callback. The argument is of type (void **)
 ** - an array of two (void *) values. The first (void *) actually points
 ** to a function of type (int (*)(void *)). In order to invoke the connections
 ** busy-handler, this function should be invoked with the second (void *) in
 ** the array as the only argument. If it returns non-zero, then the operation
 ** should be retried. If it returns zero, the custom VFS should abandon the
 ** current operation.
 **
 ** <li>[[SQLITE_FCNTL_TEMPFILENAME]]
 ** ^Application can invoke the [SQLITE_FCNTL_TEMPFILENAME] file-control
 ** to have SQLite generate a
 ** temporary filename using the same algorithm that is followed to generate
 ** temporary filenames for TEMP tables and other internal uses.  The
 ** argument should be a char** which will be filled with the filename
 ** written into memory obtained from [sqlite3_malloc()].  The caller should
 ** invoke [sqlite3_free()] on the result to avoid a memory leak.
 **
 ** <li>[[SQLITE_FCNTL_MMAP_SIZE]]
 ** The [SQLITE_FCNTL_MMAP_SIZE] file control is used to query or set the
 ** maximum number of bytes that will be used for memory-mapped I/O.
 ** The argument is a pointer to a value of type sqlite3_int64 that
 ** is an advisory maximum number of bytes in the file to memory map.  The
 ** pointer is overwritten with the old value.  The limit is not changed if
 ** the value originally pointed to is negative, and so the current limit 
 ** can be queried by passing in a pointer to a negative number.  This
 ** file-control is used internally to implement [PRAGMA mmap_size].
 **
 ** <li>[[SQLITE_FCNTL_TRACE]]
 ** The [SQLITE_FCNTL_TRACE] file control provides advisory information
 ** to the VFS about what the higher layers of the SQLite stack are doing.
 ** This file control is used by some VFS activity tracing [shims].
 ** The argument is a zero-terminated string.  Higher layers in the
 ** SQLite stack may generate instances of this file control if
 ** the [SQLITE_USE_FCNTL_TRACE] compile-time option is enabled.
 **
 ** <li>[[SQLITE_FCNTL_HAS_MOVED]]
 ** The [SQLITE_FCNTL_HAS_MOVED] file control interprets its argument as a
 ** pointer to an integer and it writes a boolean into that integer depending
 ** on whether or not the file has been renamed, moved, or deleted since it
 ** was first opened.
 **
 ** <li>[[SQLITE_FCNTL_WIN32_GET_HANDLE]]
 ** The [SQLITE_FCNTL_WIN32_GET_HANDLE] opcode can be used to obtain the
 ** underlying native file handle associated with a file handle.  This file
 ** control interprets its argument as a pointer to a native file handle and
 ** writes the resulting value there.
 **
 ** <li>[[SQLITE_FCNTL_WIN32_SET_HANDLE]]
 ** The [SQLITE_FCNTL_WIN32_SET_HANDLE] opcode is used for debugging.  This
 ** opcode causes the xFileControl method to swap the file handle with the one
 ** pointed to by the pArg argument.  This capability is used during testing
 ** and only needs to be supported when SQLITE_TEST is defined.
 **
 ** <li>[[SQLITE_FCNTL_WAL_BLOCK]]
 ** The [SQLITE_FCNTL_WAL_BLOCK] is a signal to the VFS layer that it might
 ** be advantageous to block on the next WAL lock if the lock is not immediately
 ** available.  The WAL subsystem issues this signal during rare
 ** circumstances in order to fix a problem with priority inversion.
 ** Applications should <em>not</em> use this file-control.
 **
 ** <li>[[SQLITE_FCNTL_ZIPVFS]]
 ** The [SQLITE_FCNTL_ZIPVFS] opcode is implemented by zipvfs only. All other
 ** VFS should return SQLITE_NOTFOUND for this opcode.
 **
 ** <li>[[SQLITE_FCNTL_RBU]]
 ** The [SQLITE_FCNTL_RBU] opcode is implemented by the special VFS used by
 ** the RBU extension only.  All other VFS should return SQLITE_NOTFOUND for
 ** this opcode.  
 **
 ** <li>[[SQLITE_FCNTL_BEGIN_ATOMIC_WRITE]]
 ** If the [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] opcode returns SQLITE_OK, then
 ** the file descriptor is placed in "batch write mode", which
 ** means all subsequent write operations will be deferred and done
 ** atomically at the next [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE].  Systems
 ** that do not support batch atomic writes will return SQLITE_NOTFOUND.
 ** ^Following a successful SQLITE_FCNTL_BEGIN_ATOMIC_WRITE and prior to
 ** the closing [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] or
 ** [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE], SQLite will make
 ** no VFS interface calls on the same [sqlite3_file] file descriptor
 ** except for calls to the xWrite method and the xFileControl method
 ** with [SQLITE_FCNTL_SIZE_HINT].
 **
 ** <li>[[SQLITE_FCNTL_COMMIT_ATOMIC_WRITE]]
 ** The [SQLITE_FCNTL_COMMIT_ATOMIC_WRITE] opcode causes all write
 ** operations since the previous successful call to 
 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be performed atomically.
 ** This file control returns [SQLITE_OK] if and only if the writes were
 ** all performed successfully and have been committed to persistent storage.
 ** ^Regardless of whether or not it is successful, this file control takes
 ** the file descriptor out of batch write mode so that all subsequent
 ** write operations are independent.
 ** ^SQLite will never invoke SQLITE_FCNTL_COMMIT_ATOMIC_WRITE without
 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
 **
 ** <li>[[SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE]]
 ** The [SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE] opcode causes all write
 ** operations since the previous successful call to 
 ** [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE] to be rolled back.
 ** ^This file control takes the file descriptor out of batch write mode
 ** so that all subsequent write operations are independent.
 ** ^SQLite will never invoke SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE without
 ** a prior successful call to [SQLITE_FCNTL_BEGIN_ATOMIC_WRITE].
 ** </ul>
 */
 #define SQLITE_FCNTL_LOCKSTATE               1
 #define SQLITE_FCNTL_GET_LOCKPROXYFILE       2
 #define SQLITE_FCNTL_SET_LOCKPROXYFILE       3
 #define SQLITE_FCNTL_LAST_ERRNO              4
 #define SQLITE_FCNTL_SIZE_HINT               5
 #define SQLITE_FCNTL_CHUNK_SIZE              6
 #define SQLITE_FCNTL_FILE_POINTER            7
 #define SQLITE_FCNTL_SYNC_OMITTED            8
 #define SQLITE_FCNTL_WIN32_AV_RETRY          9
 #define SQLITE_FCNTL_PERSIST_WAL            10
 #define SQLITE_FCNTL_OVERWRITE              11
 #define SQLITE_FCNTL_VFSNAME                12
 #define SQLITE_FCNTL_POWERSAFE_OVERWRITE    13
 #define SQLITE_FCNTL_PRAGMA                 14
 #define SQLITE_FCNTL_BUSYHANDLER            15
 #define SQLITE_FCNTL_TEMPFILENAME           16
 #define SQLITE_FCNTL_MMAP_SIZE              18
 #define SQLITE_FCNTL_TRACE                  19
 #define SQLITE_FCNTL_HAS_MOVED              20
 #define SQLITE_FCNTL_SYNC                   21
 #define SQLITE_FCNTL_COMMIT_PHASETWO        22
 #define SQLITE_FCNTL_WIN32_SET_HANDLE       23
 #define SQLITE_FCNTL_WAL_BLOCK              24
 #define SQLITE_FCNTL_ZIPVFS                 25
 #define SQLITE_FCNTL_RBU                    26
 #define SQLITE_FCNTL_VFS_POINTER            27
 #define SQLITE_FCNTL_JOURNAL_POINTER        28
 #define SQLITE_FCNTL_WIN32_GET_HANDLE       29
 #define SQLITE_FCNTL_PDB                    30
 #define SQLITE_FCNTL_BEGIN_ATOMIC_WRITE     31
 #define SQLITE_FCNTL_COMMIT_ATOMIC_WRITE    32
 #define SQLITE_FCNTL_ROLLBACK_ATOMIC_WRITE  33
 
 /* deprecated names */
 #define SQLITE_GET_LOCKPROXYFILE      SQLITE_FCNTL_GET_LOCKPROXYFILE
 #define SQLITE_SET_LOCKPROXYFILE      SQLITE_FCNTL_SET_LOCKPROXYFILE
 #define SQLITE_LAST_ERRNO             SQLITE_FCNTL_LAST_ERRNO
 
 
 /*
 ** CAPI3REF: Mutex Handle
 **
 ** The mutex module within SQLite defines [sqlite3_mutex] to be an
 ** abstract type for a mutex object.  The SQLite core never looks
 ** at the internal representation of an [sqlite3_mutex].  It only
 ** deals with pointers to the [sqlite3_mutex] object.
 **
 ** Mutexes are created using [sqlite3_mutex_alloc()].
 */
 typedef struct sqlite3_mutex sqlite3_mutex;
 
 /*
 ** CAPI3REF: Loadable Extension Thunk
 **
 ** A pointer to the opaque sqlite3_api_routines structure is passed as
 ** the third parameter to entry points of [loadable extensions].  This
 ** structure must be typedefed in order to work around compiler warnings
 ** on some platforms.
 */
 typedef struct sqlite3_api_routines sqlite3_api_routines;
 
 /*
 ** CAPI3REF: OS Interface Object
 **
 ** An instance of the sqlite3_vfs object defines the interface between
 ** the SQLite core and the underlying operating system.  The "vfs"
 ** in the name of the object stands for "virtual file system".  See
 ** the [VFS | VFS documentation] for further information.
 **
 ** The VFS interface is sometimes extended by adding new methods onto
 ** the end.  Each time such an extension occurs, the iVersion field
 ** is incremented.  The iVersion value started out as 1 in
 ** SQLite [version 3.5.0] on [dateof:3.5.0], then increased to 2
 ** with SQLite [version 3.7.0] on [dateof:3.7.0], and then increased
 ** to 3 with SQLite [version 3.7.6] on [dateof:3.7.6].  Additional fields
 ** may be appended to the sqlite3_vfs object and the iVersion value
 ** may increase again in future versions of SQLite.
 ** Note that the structure
 ** of the sqlite3_vfs object changes in the transition from
 ** SQLite [version 3.5.9] to [version 3.6.0] on [dateof:3.6.0]
 ** and yet the iVersion field was not modified.
 **
 ** The szOsFile field is the size of the subclassed [sqlite3_file]
 ** structure used by this VFS.  mxPathname is the maximum length of
 ** a pathname in this VFS.
 **
 ** Registered sqlite3_vfs objects are kept on a linked list formed by
 ** the pNext pointer.  The [sqlite3_vfs_register()]
 ** and [sqlite3_vfs_unregister()] interfaces manage this list
 ** in a thread-safe way.  The [sqlite3_vfs_find()] interface
 ** searches the list.  Neither the application code nor the VFS
 ** implementation should use the pNext pointer.
 **
 ** The pNext field is the only field in the sqlite3_vfs
 ** structure that SQLite will ever modify.  SQLite will only access
 ** or modify this field while holding a particular static mutex.
 ** The application should never modify anything within the sqlite3_vfs
 ** object once the object has been registered.
 **
 ** The zName field holds the name of the VFS module.  The name must
 ** be unique across all VFS modules.
 **
 ** [[sqlite3_vfs.xOpen]]
 ** ^SQLite guarantees that the zFilename parameter to xOpen
 ** is either a NULL pointer or string obtained
 ** from xFullPathname() with an optional suffix added.
 ** ^If a suffix is added to the zFilename parameter, it will
 ** consist of a single "-" character followed by no more than
 ** 11 alphanumeric and/or "-" characters.
 ** ^SQLite further guarantees that
 ** the string will be valid and unchanged until xClose() is
 ** called. Because of the previous sentence,
 ** the [sqlite3_file] can safely store a pointer to the
 ** filename if it needs to remember the filename for some reason.
 ** If the zFilename parameter to xOpen is a NULL pointer then xOpen
 ** must invent its own temporary name for the file.  ^Whenever the 
 ** xFilename parameter is NULL it will also be the case that the
 ** flags parameter will include [SQLITE_OPEN_DELETEONCLOSE].
 **
 ** The flags argument to xOpen() includes all bits set in
 ** the flags argument to [sqlite3_open_v2()].  Or if [sqlite3_open()]
 ** or [sqlite3_open16()] is used, then flags includes at least
 ** [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]. 
 ** If xOpen() opens a file read-only then it sets *pOutFlags to
 ** include [SQLITE_OPEN_READONLY].  Other bits in *pOutFlags may be set.
 **
 ** ^(SQLite will also add one of the following flags to the xOpen()
 ** call, depending on the object being opened:
 **
 ** <ul>
 ** <li>  [SQLITE_OPEN_MAIN_DB]
 ** <li>  [SQLITE_OPEN_MAIN_JOURNAL]
 ** <li>  [SQLITE_OPEN_TEMP_DB]
 ** <li>  [SQLITE_OPEN_TEMP_JOURNAL]
 ** <li>  [SQLITE_OPEN_TRANSIENT_DB]
 ** <li>  [SQLITE_OPEN_SUBJOURNAL]
 ** <li>  [SQLITE_OPEN_MASTER_JOURNAL]
 ** <li>  [SQLITE_OPEN_WAL]
 ** </ul>)^
 **
 ** The file I/O implementation can use the object type flags to
 ** change the way it deals with files.  For example, an application
 ** that does not care about crash recovery or rollback might make
 ** the open of a journal file a no-op.  Writes to this journal would
 ** also be no-ops, and any attempt to read the journal would return
 ** SQLITE_IOERR.  Or the implementation might recognize that a database
 ** file will be doing page-aligned sector reads and writes in a random
 ** order and set up its I/O subsystem accordingly.
 **
 ** SQLite might also add one of the following flags to the xOpen method:
 **
 ** <ul>
 ** <li> [SQLITE_OPEN_DELETEONCLOSE]
 ** <li> [SQLITE_OPEN_EXCLUSIVE]
 ** </ul>
 **
 ** The [SQLITE_OPEN_DELETEONCLOSE] flag means the file should be
 ** deleted when it is closed.  ^The [SQLITE_OPEN_DELETEONCLOSE]
 ** will be set for TEMP databases and their journals, transient
 ** databases, and subjournals.
 **
 ** ^The [SQLITE_OPEN_EXCLUSIVE] flag is always used in conjunction
 ** with the [SQLITE_OPEN_CREATE] flag, which are both directly
 ** analogous to the O_EXCL and O_CREAT flags of the POSIX open()
 ** API.  The SQLITE_OPEN_EXCLUSIVE flag, when paired with the 
 ** SQLITE_OPEN_CREATE, is used to indicate that file should always
 ** be created, and that it is an error if it already exists.
 ** It is <i>not</i> used to indicate the file should be opened 
 ** for exclusive access.
 **
 ** ^At least szOsFile bytes of memory are allocated by SQLite
 ** to hold the  [sqlite3_file] structure passed as the third
 ** argument to xOpen.  The xOpen method does not have to
 ** allocate the structure; it should just fill it in.  Note that
 ** the xOpen method must set the sqlite3_file.pMethods to either
 ** a valid [sqlite3_io_methods] object or to NULL.  xOpen must do
 ** this even if the open fails.  SQLite expects that the sqlite3_file.pMethods
 ** element will be valid after xOpen returns regardless of the success
 ** or failure of the xOpen call.
 **
 ** [[sqlite3_vfs.xAccess]]
 ** ^The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS]
 ** to test for the existence of a file, or [SQLITE_ACCESS_READWRITE] to
 ** test whether a file is readable and writable, or [SQLITE_ACCESS_READ]
 ** to test whether a file is at least readable.   The file can be a
 ** directory.
 **
 ** ^SQLite will always allocate at least mxPathname+1 bytes for the
 ** output buffer xFullPathname.  The exact size of the output buffer
 ** is also passed as a parameter to both  methods. If the output buffer
 ** is not large enough, [SQLITE_CANTOPEN] should be returned. Since this is
 ** handled as a fatal error by SQLite, vfs implementations should endeavor
 ** to prevent this by setting mxPathname to a sufficiently large value.
 **
 ** The xRandomness(), xSleep(), xCurrentTime(), and xCurrentTimeInt64()
 ** interfaces are not strictly a part of the filesystem, but they are
 ** included in the VFS structure for completeness.
 ** The xRandomness() function attempts to return nBytes bytes
 ** of good-quality randomness into zOut.  The return value is
 ** the actual number of bytes of randomness obtained.
 ** The xSleep() method causes the calling thread to sleep for at
 ** least the number of microseconds given.  ^The xCurrentTime()
 ** method returns a Julian Day Number for the current date and time as
 ** a floating point value.
 ** ^The xCurrentTimeInt64() method returns, as an integer, the Julian
 ** Day Number multiplied by 86400000 (the number of milliseconds in 
 ** a 24-hour day).  
 ** ^SQLite will use the xCurrentTimeInt64() method to get the current
 ** date and time if that method is available (if iVersion is 2 or 
 ** greater and the function pointer is not NULL) and will fall back
 ** to xCurrentTime() if xCurrentTimeInt64() is unavailable.
 **
 ** ^The xSetSystemCall(), xGetSystemCall(), and xNestSystemCall() interfaces
 ** are not used by the SQLite core.  These optional interfaces are provided
 ** by some VFSes to facilitate testing of the VFS code. By overriding 
 ** system calls with functions under its control, a test program can
 ** simulate faults and error conditions that would otherwise be difficult
 ** or impossible to induce.  The set of system calls that can be overridden
 ** varies from one VFS to another, and from one version of the same VFS to the
 ** next.  Applications that use these interfaces must be prepared for any
 ** or all of these interfaces to be NULL or for their behavior to change
 ** from one release to the next.  Applications must not attempt to access
 ** any of these methods if the iVersion of the VFS is less than 3.
 */
 typedef struct sqlite3_vfs sqlite3_vfs;
 typedef void (*sqlite3_syscall_ptr)(void);
 struct sqlite3_vfs {
   int iVersion;            /* Structure version number (currently 3) */
   int szOsFile;            /* Size of subclassed sqlite3_file */
   int mxPathname;          /* Maximum file pathname length */
   sqlite3_vfs *pNext;      /* Next registered VFS */
   const char *zName;       /* Name of this virtual file system */
   void *pAppData;          /* Pointer to application-specific data */
   int (*xOpen)(sqlite3_vfs*, const char *zName, sqlite3_file*,
                int flags, int *pOutFlags);
   int (*xDelete)(sqlite3_vfs*, const char *zName, int syncDir);
   int (*xAccess)(sqlite3_vfs*, const char *zName, int flags, int *pResOut);
   int (*xFullPathname)(sqlite3_vfs*, const char *zName, int nOut, char *zOut);
   void *(*xDlOpen)(sqlite3_vfs*, const char *zFilename);
   void (*xDlError)(sqlite3_vfs*, int nByte, char *zErrMsg);
   void (*(*xDlSym)(sqlite3_vfs*,void*, const char *zSymbol))(void);
   void (*xDlClose)(sqlite3_vfs*, void*);
   int (*xRandomness)(sqlite3_vfs*, int nByte, char *zOut);
   int (*xSleep)(sqlite3_vfs*, int microseconds);
   int (*xCurrentTime)(sqlite3_vfs*, double*);
   int (*xGetLastError)(sqlite3_vfs*, int, char *);
   /*
   ** The methods above are in version 1 of the sqlite_vfs object
   ** definition.  Those that follow are added in version 2 or later
   */
   int (*xCurrentTimeInt64)(sqlite3_vfs*, sqlite3_int64*);
   /*
   ** The methods above are in versions 1 and 2 of the sqlite_vfs object.
   ** Those below are for version 3 and greater.
   */
   int (*xSetSystemCall)(sqlite3_vfs*, const char *zName, sqlite3_syscall_ptr);
   sqlite3_syscall_ptr (*xGetSystemCall)(sqlite3_vfs*, const char *zName);
   const char *(*xNextSystemCall)(sqlite3_vfs*, const char *zName);
   /*
   ** The methods above are in versions 1 through 3 of the sqlite_vfs object.
   ** New fields may be appended in future versions.  The iVersion
   ** value will increment whenever this happens. 
   */
 };
 
 /*
 ** CAPI3REF: Flags for the xAccess VFS method
 **
 ** These integer constants can be used as the third parameter to
 ** the xAccess method of an [sqlite3_vfs] object.  They determine
 ** what kind of permissions the xAccess method is looking for.
 ** With SQLITE_ACCESS_EXISTS, the xAccess method
 ** simply checks whether the file exists.
 ** With SQLITE_ACCESS_READWRITE, the xAccess method
 ** checks whether the named directory is both readable and writable
 ** (in other words, if files can be added, removed, and renamed within
 ** the directory).
 ** The SQLITE_ACCESS_READWRITE constant is currently used only by the
 ** [temp_store_directory pragma], though this could change in a future
 ** release of SQLite.
 ** With SQLITE_ACCESS_READ, the xAccess method
 ** checks whether the file is readable.  The SQLITE_ACCESS_READ constant is
 ** currently unused, though it might be used in a future release of
 ** SQLite.
 */
 #define SQLITE_ACCESS_EXISTS    0
 #define SQLITE_ACCESS_READWRITE 1   /* Used by PRAGMA temp_store_directory */
 #define SQLITE_ACCESS_READ      2   /* Unused */
 
 /*
 ** CAPI3REF: Flags for the xShmLock VFS method
 **
 ** These integer constants define the various locking operations
 ** allowed by the xShmLock method of [sqlite3_io_methods].  The
 ** following are the only legal combinations of flags to the
 ** xShmLock method:
 **
 ** <ul>
 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_SHARED
 ** <li>  SQLITE_SHM_LOCK | SQLITE_SHM_EXCLUSIVE
 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_SHARED
 ** <li>  SQLITE_SHM_UNLOCK | SQLITE_SHM_EXCLUSIVE
 ** </ul>
 **
 ** When unlocking, the same SHARED or EXCLUSIVE flag must be supplied as
 ** was given on the corresponding lock.  
 **
 ** The xShmLock method can transition between unlocked and SHARED or
 ** between unlocked and EXCLUSIVE.  It cannot transition between SHARED
 ** and EXCLUSIVE.
 */
 #define SQLITE_SHM_UNLOCK       1
 #define SQLITE_SHM_LOCK         2
 #define SQLITE_SHM_SHARED       4
 #define SQLITE_SHM_EXCLUSIVE    8
 
 /*
 ** CAPI3REF: Maximum xShmLock index
 **
 ** The xShmLock method on [sqlite3_io_methods] may use values
 ** between 0 and this upper bound as its "offset" argument.
 ** The SQLite core will never attempt to acquire or release a
 ** lock outside of this range
 */
 #define SQLITE_SHM_NLOCK        8
 
 
 /*
 ** CAPI3REF: Initialize The SQLite Library
 **
 ** ^The sqlite3_initialize() routine initializes the
 ** SQLite library.  ^The sqlite3_shutdown() routine
 ** deallocates any resources that were allocated by sqlite3_initialize().
 ** These routines are designed to aid in process initialization and
 ** shutdown on embedded systems.  Workstation applications using
 ** SQLite normally do not need to invoke either of these routines.
 **
 ** A call to sqlite3_initialize() is an "effective" call if it is
 ** the first time sqlite3_initialize() is invoked during the lifetime of
 ** the process, or if it is the first time sqlite3_initialize() is invoked
 ** following a call to sqlite3_shutdown().  ^(Only an effective call
 ** of sqlite3_initialize() does any initialization.  All other calls
 ** are harmless no-ops.)^
 **
 ** A call to sqlite3_shutdown() is an "effective" call if it is the first
 ** call to sqlite3_shutdown() since the last sqlite3_initialize().  ^(Only
 ** an effective call to sqlite3_shutdown() does any deinitialization.
 ** All other valid calls to sqlite3_shutdown() are harmless no-ops.)^
 **
 ** The sqlite3_initialize() interface is threadsafe, but sqlite3_shutdown()
 ** is not.  The sqlite3_shutdown() interface must only be called from a
 ** single thread.  All open [database connections] must be closed and all
 ** other SQLite resources must be deallocated prior to invoking
 ** sqlite3_shutdown().
 **
 ** Among other things, ^sqlite3_initialize() will invoke
 ** sqlite3_os_init().  Similarly, ^sqlite3_shutdown()
 ** will invoke sqlite3_os_end().
 **
 ** ^The sqlite3_initialize() routine returns [SQLITE_OK] on success.
 ** ^If for some reason, sqlite3_initialize() is unable to initialize
 ** the library (perhaps it is unable to allocate a needed resource such
 ** as a mutex) it returns an [error code] other than [SQLITE_OK].
 **
 ** ^The sqlite3_initialize() routine is called internally by many other
 ** SQLite interfaces so that an application usually does not need to
 ** invoke sqlite3_initialize() directly.  For example, [sqlite3_open()]
 ** calls sqlite3_initialize() so the SQLite library will be automatically
 ** initialized when [sqlite3_open()] is called if it has not be initialized
 ** already.  ^However, if SQLite is compiled with the [SQLITE_OMIT_AUTOINIT]
 ** compile-time option, then the automatic calls to sqlite3_initialize()
 ** are omitted and the application must call sqlite3_initialize() directly
 ** prior to using any other SQLite interface.  For maximum portability,
 ** it is recommended that applications always invoke sqlite3_initialize()
 ** directly prior to using any other SQLite interface.  Future releases
 ** of SQLite may require this.  In other words, the behavior exhibited
 ** when SQLite is compiled with [SQLITE_OMIT_AUTOINIT] might become the
 ** default behavior in some future release of SQLite.
 **
 ** The sqlite3_os_init() routine does operating-system specific
 ** initialization of the SQLite library.  The sqlite3_os_end()
 ** routine undoes the effect of sqlite3_os_init().  Typical tasks
 ** performed by these routines include allocation or deallocation
 ** of static resources, initialization of global variables,
 ** setting up a default [sqlite3_vfs] module, or setting up
 ** a default configuration using [sqlite3_config()].
 **
 ** The application should never invoke either sqlite3_os_init()
 ** or sqlite3_os_end() directly.  The application should only invoke
 ** sqlite3_initialize() and sqlite3_shutdown().  The sqlite3_os_init()
 ** interface is called automatically by sqlite3_initialize() and
 ** sqlite3_os_end() is called by sqlite3_shutdown().  Appropriate
 ** implementations for sqlite3_os_init() and sqlite3_os_end()
 ** are built into SQLite when it is compiled for Unix, Windows, or OS/2.
 ** When [custom builds | built for other platforms]
 ** (using the [SQLITE_OS_OTHER=1] compile-time
 ** option) the application must supply a suitable implementation for
 ** sqlite3_os_init() and sqlite3_os_end().  An application-supplied
 ** implementation of sqlite3_os_init() or sqlite3_os_end()
 ** must return [SQLITE_OK] on success and some other [error code] upon
 ** failure.
 */
 SQLITE_API int sqlite3_initialize(void);
 SQLITE_API int sqlite3_shutdown(void);
 SQLITE_API int sqlite3_os_init(void);
 SQLITE_API int sqlite3_os_end(void);
 
 /*
 ** CAPI3REF: Configuring The SQLite Library
 **
 ** The sqlite3_config() interface is used to make global configuration
 ** changes to SQLite in order to tune SQLite to the specific needs of
 ** the application.  The default configuration is recommended for most
 ** applications and so this routine is usually not necessary.  It is
 ** provided to support rare applications with unusual needs.
 **
 ** <b>The sqlite3_config() interface is not threadsafe. The application
 ** must ensure that no other SQLite interfaces are invoked by other
 ** threads while sqlite3_config() is running.</b>
 **
 ** The sqlite3_config() interface
 ** may only be invoked prior to library initialization using
 ** [sqlite3_initialize()] or after shutdown by [sqlite3_shutdown()].
 ** ^If sqlite3_config() is called after [sqlite3_initialize()] and before
 ** [sqlite3_shutdown()] then it will return SQLITE_MISUSE.
 ** Note, however, that ^sqlite3_config() can be called as part of the
 ** implementation of an application-defined [sqlite3_os_init()].
 **
 ** The first argument to sqlite3_config() is an integer
 ** [configuration option] that determines
 ** what property of SQLite is to be configured.  Subsequent arguments
 ** vary depending on the [configuration option]
 ** in the first argument.
 **
 ** ^When a configuration option is set, sqlite3_config() returns [SQLITE_OK].
 ** ^If the option is unknown or SQLite is unable to set the option
 ** then this routine returns a non-zero [error code].
 */
 SQLITE_API int sqlite3_config(int, ...);
 
 /*
 ** CAPI3REF: Configure database connections
 ** METHOD: sqlite3
 **
 ** The sqlite3_db_config() interface is used to make configuration
 ** changes to a [database connection].  The interface is similar to
 ** [sqlite3_config()] except that the changes apply to a single
 ** [database connection] (specified in the first argument).
 **
 ** The second argument to sqlite3_db_config(D,V,...)  is the
 ** [SQLITE_DBCONFIG_LOOKASIDE | configuration verb] - an integer code 
 ** that indicates what aspect of the [database connection] is being configured.
 ** Subsequent arguments vary depending on the configuration verb.
 **
 ** ^Calls to sqlite3_db_config() return SQLITE_OK if and only if
 ** the call is considered successful.
 */
 SQLITE_API int sqlite3_db_config(sqlite3*, int op, ...);
 
 /*
 ** CAPI3REF: Memory Allocation Routines
 **
 ** An instance of this object defines the interface between SQLite
 ** and low-level memory allocation routines.
 **
 ** This object is used in only one place in the SQLite interface.
 ** A pointer to an instance of this object is the argument to
 ** [sqlite3_config()] when the configuration option is
 ** [SQLITE_CONFIG_MALLOC] or [SQLITE_CONFIG_GETMALLOC].  
 ** By creating an instance of this object
 ** and passing it to [sqlite3_config]([SQLITE_CONFIG_MALLOC])
 ** during configuration, an application can specify an alternative
 ** memory allocation subsystem for SQLite to use for all of its
 ** dynamic memory needs.
 **
 ** Note that SQLite comes with several [built-in memory allocators]
 ** that are perfectly adequate for the overwhelming majority of applications
 ** and that this object is only useful to a tiny minority of applications
 ** with specialized memory allocation requirements.  This object is
 ** also used during testing of SQLite in order to specify an alternative
 ** memory allocator that simulates memory out-of-memory conditions in
 ** order to verify that SQLite recovers gracefully from such
 ** conditions.
 **
 ** The xMalloc, xRealloc, and xFree methods must work like the
 ** malloc(), realloc() and free() functions from the standard C library.
 ** ^SQLite guarantees that the second argument to
 ** xRealloc is always a value returned by a prior call to xRoundup.
 **
 ** xSize should return the allocated size of a memory allocation
 ** previously obtained from xMalloc or xRealloc.  The allocated size
 ** is always at least as big as the requested size but may be larger.
 **
 ** The xRoundup method returns what would be the allocated size of
 ** a memory allocation given a particular requested size.  Most memory
 ** allocators round up memory allocations at least to the next multiple
 ** of 8.  Some allocators round up to a larger multiple or to a power of 2.
 ** Every memory allocation request coming in through [sqlite3_malloc()]
 ** or [sqlite3_realloc()] first calls xRoundup.  If xRoundup returns 0, 
 ** that causes the corresponding memory allocation to fail.
 **
 ** The xInit method initializes the memory allocator.  For example,
 ** it might allocate any require mutexes or initialize internal data
 ** structures.  The xShutdown method is invoked (indirectly) by
 ** [sqlite3_shutdown()] and should deallocate any resources acquired
 ** by xInit.  The pAppData pointer is used as the only parameter to
 ** xInit and xShutdown.
 **
 ** SQLite holds the [SQLITE_MUTEX_STATIC_MASTER] mutex when it invokes
 ** the xInit method, so the xInit method need not be threadsafe.  The
 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
 ** not need to be threadsafe either.  For all other methods, SQLite
 ** holds the [SQLITE_MUTEX_STATIC_MEM] mutex as long as the
 ** [SQLITE_CONFIG_MEMSTATUS] configuration option is turned on (which
 ** it is by default) and so the methods are automatically serialized.
 ** However, if [SQLITE_CONFIG_MEMSTATUS] is disabled, then the other
 ** methods must be threadsafe or else make their own arrangements for
 ** serialization.
 **
 ** SQLite will never invoke xInit() more than once without an intervening
 ** call to xShutdown().
 */
 typedef struct sqlite3_mem_methods sqlite3_mem_methods;
 struct sqlite3_mem_methods {
   void *(*xMalloc)(int);         /* Memory allocation function */
   void (*xFree)(void*);          /* Free a prior allocation */
   void *(*xRealloc)(void*,int);  /* Resize an allocation */
   int (*xSize)(void*);           /* Return the size of an allocation */
   int (*xRoundup)(int);          /* Round up request size to allocation size */
   int (*xInit)(void*);           /* Initialize the memory allocator */
   void (*xShutdown)(void*);      /* Deinitialize the memory allocator */
   void *pAppData;                /* Argument to xInit() and xShutdown() */
 };
 
 /*
 ** CAPI3REF: Configuration Options
 ** KEYWORDS: {configuration option}
 **
 ** These constants are the available integer configuration options that
 ** can be passed as the first argument to the [sqlite3_config()] interface.
 **
 ** New configuration options may be added in future releases of SQLite.
 ** Existing configuration options might be discontinued.  Applications
 ** should check the return code from [sqlite3_config()] to make sure that
 ** the call worked.  The [sqlite3_config()] interface will return a
 ** non-zero [error code] if a discontinued or unsupported configuration option
 ** is invoked.
 **
 ** <dl>
 ** [[SQLITE_CONFIG_SINGLETHREAD]] <dt>SQLITE_CONFIG_SINGLETHREAD</dt>
 ** <dd>There are no arguments to this option.  ^This option sets the
 ** [threading mode] to Single-thread.  In other words, it disables
 ** all mutexing and puts SQLite into a mode where it can only be used
 ** by a single thread.   ^If SQLite is compiled with
 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
 ** it is not possible to change the [threading mode] from its default
 ** value of Single-thread and so [sqlite3_config()] will return 
 ** [SQLITE_ERROR] if called with the SQLITE_CONFIG_SINGLETHREAD
 ** configuration option.</dd>
 **
 ** [[SQLITE_CONFIG_MULTITHREAD]] <dt>SQLITE_CONFIG_MULTITHREAD</dt>
 ** <dd>There are no arguments to this option.  ^This option sets the
 ** [threading mode] to Multi-thread.  In other words, it disables
 ** mutexing on [database connection] and [prepared statement] objects.
 ** The application is responsible for serializing access to
 ** [database connections] and [prepared statements].  But other mutexes
 ** are enabled so that SQLite will be safe to use in a multi-threaded
 ** environment as long as no two threads attempt to use the same
 ** [database connection] at the same time.  ^If SQLite is compiled with
 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
 ** it is not possible to set the Multi-thread [threading mode] and
 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
 ** SQLITE_CONFIG_MULTITHREAD configuration option.</dd>
 **
 ** [[SQLITE_CONFIG_SERIALIZED]] <dt>SQLITE_CONFIG_SERIALIZED</dt>
 ** <dd>There are no arguments to this option.  ^This option sets the
 ** [threading mode] to Serialized. In other words, this option enables
 ** all mutexes including the recursive
 ** mutexes on [database connection] and [prepared statement] objects.
 ** In this mode (which is the default when SQLite is compiled with
 ** [SQLITE_THREADSAFE=1]) the SQLite library will itself serialize access
 ** to [database connections] and [prepared statements] so that the
 ** application is free to use the same [database connection] or the
 ** same [prepared statement] in different threads at the same time.
 ** ^If SQLite is compiled with
 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
 ** it is not possible to set the Serialized [threading mode] and
 ** [sqlite3_config()] will return [SQLITE_ERROR] if called with the
 ** SQLITE_CONFIG_SERIALIZED configuration option.</dd>
 **
 ** [[SQLITE_CONFIG_MALLOC]] <dt>SQLITE_CONFIG_MALLOC</dt>
 ** <dd> ^(The SQLITE_CONFIG_MALLOC option takes a single argument which is 
 ** a pointer to an instance of the [sqlite3_mem_methods] structure.
 ** The argument specifies
 ** alternative low-level memory allocation routines to be used in place of
 ** the memory allocation routines built into SQLite.)^ ^SQLite makes
 ** its own private copy of the content of the [sqlite3_mem_methods] structure
 ** before the [sqlite3_config()] call returns.</dd>
 **
 ** [[SQLITE_CONFIG_GETMALLOC]] <dt>SQLITE_CONFIG_GETMALLOC</dt>
 ** <dd> ^(The SQLITE_CONFIG_GETMALLOC option takes a single argument which
 ** is a pointer to an instance of the [sqlite3_mem_methods] structure.
 ** The [sqlite3_mem_methods]
 ** structure is filled with the currently defined memory allocation routines.)^
 ** This option can be used to overload the default memory allocation
 ** routines with a wrapper that simulations memory allocation failure or
 ** tracks memory usage, for example. </dd>
 **
 ** [[SQLITE_CONFIG_SMALL_MALLOC]] <dt>SQLITE_CONFIG_SMALL_MALLOC</dt>
 ** <dd> ^The SQLITE_CONFIG_SMALL_MALLOC option takes single argument of
 ** type int, interpreted as a boolean, which if true provides a hint to
 ** SQLite that it should avoid large memory allocations if possible.
 ** SQLite will run faster if it is free to make large memory allocations,
 ** but some application might prefer to run slower in exchange for
 ** guarantees about memory fragmentation that are possible if large
 ** allocations are avoided.  This hint is normally off.
 ** </dd>
 **
 ** [[SQLITE_CONFIG_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>
 ** <dd> ^The SQLITE_CONFIG_MEMSTATUS option takes single argument of type int,
 ** interpreted as a boolean, which enables or disables the collection of
 ** memory allocation statistics. ^(When memory allocation statistics are
 ** disabled, the following SQLite interfaces become non-operational:
 **   <ul>
 **   <li> [sqlite3_memory_used()]
 **   <li> [sqlite3_memory_highwater()]
 **   <li> [sqlite3_soft_heap_limit64()]
 **   <li> [sqlite3_status64()]
 **   </ul>)^
 ** ^Memory allocation statistics are enabled by default unless SQLite is
 ** compiled with [SQLITE_DEFAULT_MEMSTATUS]=0 in which case memory
 ** allocation statistics are disabled by default.
 ** </dd>
 **
 ** [[SQLITE_CONFIG_SCRATCH]] <dt>SQLITE_CONFIG_SCRATCH</dt>
 ** <dd> The SQLITE_CONFIG_SCRATCH option is no longer used.
 ** </dd>
 **
 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>
 ** <dd> ^The SQLITE_CONFIG_PAGECACHE option specifies a memory pool
 ** that SQLite can use for the database page cache with the default page
 ** cache implementation.  
 ** This configuration option is a no-op if an application-define page
 ** cache implementation is loaded using the [SQLITE_CONFIG_PCACHE2].
 ** ^There are three arguments to SQLITE_CONFIG_PAGECACHE: A pointer to
 ** 8-byte aligned memory (pMem), the size of each page cache line (sz),
 ** and the number of cache lines (N).
 ** The sz argument should be the size of the largest database page
 ** (a power of two between 512 and 65536) plus some extra bytes for each
 ** page header.  ^The number of extra bytes needed by the page header
 ** can be determined using [SQLITE_CONFIG_PCACHE_HDRSZ].
 ** ^It is harmless, apart from the wasted memory,
 ** for the sz parameter to be larger than necessary.  The pMem
 ** argument must be either a NULL pointer or a pointer to an 8-byte
 ** aligned block of memory of at least sz*N bytes, otherwise
 ** subsequent behavior is undefined.
 ** ^When pMem is not NULL, SQLite will strive to use the memory provided
 ** to satisfy page cache needs, falling back to [sqlite3_malloc()] if
 ** a page cache line is larger than sz bytes or if all of the pMem buffer
 ** is exhausted.
 ** ^If pMem is NULL and N is non-zero, then each database connection
 ** does an initial bulk allocation for page cache memory
 ** from [sqlite3_malloc()] sufficient for N cache lines if N is positive or
 ** of -1024*N bytes if N is negative, . ^If additional
 ** page cache memory is needed beyond what is provided by the initial
 ** allocation, then SQLite goes to [sqlite3_malloc()] separately for each
 ** additional cache line. </dd>
 **
 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>
 ** <dd> ^The SQLITE_CONFIG_HEAP option specifies a static memory buffer 
 ** that SQLite will use for all of its dynamic memory allocation needs
 ** beyond those provided for by [SQLITE_CONFIG_PAGECACHE].
 ** ^The SQLITE_CONFIG_HEAP option is only available if SQLite is compiled
 ** with either [SQLITE_ENABLE_MEMSYS3] or [SQLITE_ENABLE_MEMSYS5] and returns
 ** [SQLITE_ERROR] if invoked otherwise.
 ** ^There are three arguments to SQLITE_CONFIG_HEAP:
 ** An 8-byte aligned pointer to the memory,
 ** the number of bytes in the memory buffer, and the minimum allocation size.
 ** ^If the first pointer (the memory pointer) is NULL, then SQLite reverts
 ** to using its default memory allocator (the system malloc() implementation),
 ** undoing any prior invocation of [SQLITE_CONFIG_MALLOC].  ^If the
 ** memory pointer is not NULL then the alternative memory
 ** allocator is engaged to handle all of SQLites memory allocation needs.
 ** The first pointer (the memory pointer) must be aligned to an 8-byte
 ** boundary or subsequent behavior of SQLite will be undefined.
 ** The minimum allocation size is capped at 2**12. Reasonable values
 ** for the minimum allocation size are 2**5 through 2**8.</dd>
 **
 ** [[SQLITE_CONFIG_MUTEX]] <dt>SQLITE_CONFIG_MUTEX</dt>
 ** <dd> ^(The SQLITE_CONFIG_MUTEX option takes a single argument which is a
 ** pointer to an instance of the [sqlite3_mutex_methods] structure.
 ** The argument specifies alternative low-level mutex routines to be used
 ** in place the mutex routines built into SQLite.)^  ^SQLite makes a copy of
 ** the content of the [sqlite3_mutex_methods] structure before the call to
 ** [sqlite3_config()] returns. ^If SQLite is compiled with
 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
 ** the entire mutexing subsystem is omitted from the build and hence calls to
 ** [sqlite3_config()] with the SQLITE_CONFIG_MUTEX configuration option will
 ** return [SQLITE_ERROR].</dd>
 **
 ** [[SQLITE_CONFIG_GETMUTEX]] <dt>SQLITE_CONFIG_GETMUTEX</dt>
 ** <dd> ^(The SQLITE_CONFIG_GETMUTEX option takes a single argument which
 ** is a pointer to an instance of the [sqlite3_mutex_methods] structure.  The
 ** [sqlite3_mutex_methods]
 ** structure is filled with the currently defined mutex routines.)^
 ** This option can be used to overload the default mutex allocation
 ** routines with a wrapper used to track mutex usage for performance
 ** profiling or testing, for example.   ^If SQLite is compiled with
 ** the [SQLITE_THREADSAFE | SQLITE_THREADSAFE=0] compile-time option then
 ** the entire mutexing subsystem is omitted from the build and hence calls to
 ** [sqlite3_config()] with the SQLITE_CONFIG_GETMUTEX configuration option will
 ** return [SQLITE_ERROR].</dd>
 **
 ** [[SQLITE_CONFIG_LOOKASIDE]] <dt>SQLITE_CONFIG_LOOKASIDE</dt>
 ** <dd> ^(The SQLITE_CONFIG_LOOKASIDE option takes two arguments that determine
 ** the default size of lookaside memory on each [database connection].
 ** The first argument is the
 ** size of each lookaside buffer slot and the second is the number of
 ** slots allocated to each database connection.)^  ^(SQLITE_CONFIG_LOOKASIDE
 ** sets the <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]
 ** option to [sqlite3_db_config()] can be used to change the lookaside
 ** configuration on individual connections.)^ </dd>
 **
 ** [[SQLITE_CONFIG_PCACHE2]] <dt>SQLITE_CONFIG_PCACHE2</dt>
 ** <dd> ^(The SQLITE_CONFIG_PCACHE2 option takes a single argument which is 
 ** a pointer to an [sqlite3_pcache_methods2] object.  This object specifies
 ** the interface to a custom page cache implementation.)^
 ** ^SQLite makes a copy of the [sqlite3_pcache_methods2] object.</dd>
 **
 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>
 ** <dd> ^(The SQLITE_CONFIG_GETPCACHE2 option takes a single argument which
 ** is a pointer to an [sqlite3_pcache_methods2] object.  SQLite copies of
 ** the current page cache implementation into that object.)^ </dd>
 **
 ** [[SQLITE_CONFIG_LOG]] <dt>SQLITE_CONFIG_LOG</dt>
 ** <dd> The SQLITE_CONFIG_LOG option is used to configure the SQLite
 ** global [error log].
 ** (^The SQLITE_CONFIG_LOG option takes two arguments: a pointer to a
 ** function with a call signature of void(*)(void*,int,const char*), 
 ** and a pointer to void. ^If the function pointer is not NULL, it is
 ** invoked by [sqlite3_log()] to process each logging event.  ^If the
 ** function pointer is NULL, the [sqlite3_log()] interface becomes a no-op.
 ** ^The void pointer that is the second argument to SQLITE_CONFIG_LOG is
 ** passed through as the first parameter to the application-defined logger
 ** function whenever that function is invoked.  ^The second parameter to
 ** the logger function is a copy of the first parameter to the corresponding
 ** [sqlite3_log()] call and is intended to be a [result code] or an
 ** [extended result code].  ^The third parameter passed to the logger is
 ** log message after formatting via [sqlite3_snprintf()].
 ** The SQLite logging interface is not reentrant; the logger function
 ** supplied by the application must not invoke any SQLite interface.
 ** In a multi-threaded application, the application-defined logger
 ** function must be threadsafe. </dd>
 **
 ** [[SQLITE_CONFIG_URI]] <dt>SQLITE_CONFIG_URI
 ** <dd>^(The SQLITE_CONFIG_URI option takes a single argument of type int.
 ** If non-zero, then URI handling is globally enabled. If the parameter is zero,
 ** then URI handling is globally disabled.)^ ^If URI handling is globally
 ** enabled, all filenames passed to [sqlite3_open()], [sqlite3_open_v2()],
 ** [sqlite3_open16()] or
 ** specified as part of [ATTACH] commands are interpreted as URIs, regardless
 ** of whether or not the [SQLITE_OPEN_URI] flag is set when the database
 ** connection is opened. ^If it is globally disabled, filenames are
 ** only interpreted as URIs if the SQLITE_OPEN_URI flag is set when the
 ** database connection is opened. ^(By default, URI handling is globally
 ** disabled. The default value may be changed by compiling with the
 ** [SQLITE_USE_URI] symbol defined.)^
 **
 ** [[SQLITE_CONFIG_COVERING_INDEX_SCAN]] <dt>SQLITE_CONFIG_COVERING_INDEX_SCAN
 ** <dd>^The SQLITE_CONFIG_COVERING_INDEX_SCAN option takes a single integer
 ** argument which is interpreted as a boolean in order to enable or disable
 ** the use of covering indices for full table scans in the query optimizer.
 ** ^The default setting is determined
 ** by the [SQLITE_ALLOW_COVERING_INDEX_SCAN] compile-time option, or is "on"
 ** if that compile-time option is omitted.
 ** The ability to disable the use of covering indices for full table scans
 ** is because some incorrectly coded legacy applications might malfunction
 ** when the optimization is enabled.  Providing the ability to
 ** disable the optimization allows the older, buggy application code to work
 ** without change even with newer versions of SQLite.
 **
 ** [[SQLITE_CONFIG_PCACHE]] [[SQLITE_CONFIG_GETPCACHE]]
 ** <dt>SQLITE_CONFIG_PCACHE and SQLITE_CONFIG_GETPCACHE
 ** <dd> These options are obsolete and should not be used by new code.
 ** They are retained for backwards compatibility but are now no-ops.
 ** </dd>
 **
 ** [[SQLITE_CONFIG_SQLLOG]]
 ** <dt>SQLITE_CONFIG_SQLLOG
 ** <dd>This option is only available if sqlite is compiled with the
 ** [SQLITE_ENABLE_SQLLOG] pre-processor macro defined. The first argument should
 ** be a pointer to a function of type void(*)(void*,sqlite3*,const char*, int).
 ** The second should be of type (void*). The callback is invoked by the library
 ** in three separate circumstances, identified by the value passed as the
 ** fourth parameter. If the fourth parameter is 0, then the database connection
 ** passed as the second argument has just been opened. The third argument
 ** points to a buffer containing the name of the main database file. If the
 ** fourth parameter is 1, then the SQL statement that the third parameter
 ** points to has just been executed. Or, if the fourth parameter is 2, then
 ** the connection being passed as the second parameter is being closed. The
 ** third parameter is passed NULL In this case.  An example of using this
 ** configuration option can be seen in the "test_sqllog.c" source file in
 ** the canonical SQLite source tree.</dd>
 **
 ** [[SQLITE_CONFIG_MMAP_SIZE]]
 ** <dt>SQLITE_CONFIG_MMAP_SIZE
 ** <dd>^SQLITE_CONFIG_MMAP_SIZE takes two 64-bit integer (sqlite3_int64) values
 ** that are the default mmap size limit (the default setting for
 ** [PRAGMA mmap_size]) and the maximum allowed mmap size limit.
 ** ^The default setting can be overridden by each database connection using
 ** either the [PRAGMA mmap_size] command, or by using the
 ** [SQLITE_FCNTL_MMAP_SIZE] file control.  ^(The maximum allowed mmap size
 ** will be silently truncated if necessary so that it does not exceed the
 ** compile-time maximum mmap size set by the
 ** [SQLITE_MAX_MMAP_SIZE] compile-time option.)^
 ** ^If either argument to this option is negative, then that argument is
 ** changed to its compile-time default.
 **
 ** [[SQLITE_CONFIG_WIN32_HEAPSIZE]]
 ** <dt>SQLITE_CONFIG_WIN32_HEAPSIZE
 ** <dd>^The SQLITE_CONFIG_WIN32_HEAPSIZE option is only available if SQLite is
 ** compiled for Windows with the [SQLITE_WIN32_MALLOC] pre-processor macro
 ** defined. ^SQLITE_CONFIG_WIN32_HEAPSIZE takes a 32-bit unsigned integer value
 ** that specifies the maximum size of the created heap.
 **
 ** [[SQLITE_CONFIG_PCACHE_HDRSZ]]
 ** <dt>SQLITE_CONFIG_PCACHE_HDRSZ
 ** <dd>^The SQLITE_CONFIG_PCACHE_HDRSZ option takes a single parameter which
 ** is a pointer to an integer and writes into that integer the number of extra
 ** bytes per page required for each page in [SQLITE_CONFIG_PAGECACHE].
 ** The amount of extra space required can change depending on the compiler,
 ** target platform, and SQLite version.
 **
 ** [[SQLITE_CONFIG_PMASZ]]
 ** <dt>SQLITE_CONFIG_PMASZ
 ** <dd>^The SQLITE_CONFIG_PMASZ option takes a single parameter which
 ** is an unsigned integer and sets the "Minimum PMA Size" for the multithreaded
 ** sorter to that integer.  The default minimum PMA Size is set by the
 ** [SQLITE_SORTER_PMASZ] compile-time option.  New threads are launched
 ** to help with sort operations when multithreaded sorting
 ** is enabled (using the [PRAGMA threads] command) and the amount of content
 ** to be sorted exceeds the page size times the minimum of the
 ** [PRAGMA cache_size] setting and this value.
 **
 ** [[SQLITE_CONFIG_STMTJRNL_SPILL]]
 ** <dt>SQLITE_CONFIG_STMTJRNL_SPILL
 ** <dd>^The SQLITE_CONFIG_STMTJRNL_SPILL option takes a single parameter which
 ** becomes the [statement journal] spill-to-disk threshold.  
 ** [Statement journals] are held in memory until their size (in bytes)
 ** exceeds this threshold, at which point they are written to disk.
 ** Or if the threshold is -1, statement journals are always held
 ** exclusively in memory.
 ** Since many statement journals never become large, setting the spill
 ** threshold to a value such as 64KiB can greatly reduce the amount of
 ** I/O required to support statement rollback.
 ** The default value for this setting is controlled by the
 ** [SQLITE_STMTJRNL_SPILL] compile-time option.
 ** </dl>
 */
 #define SQLITE_CONFIG_SINGLETHREAD  1  /* nil */
 #define SQLITE_CONFIG_MULTITHREAD   2  /* nil */
 #define SQLITE_CONFIG_SERIALIZED    3  /* nil */
 #define SQLITE_CONFIG_MALLOC        4  /* sqlite3_mem_methods* */
 #define SQLITE_CONFIG_GETMALLOC     5  /* sqlite3_mem_methods* */
 #define SQLITE_CONFIG_SCRATCH       6  /* No longer used */
 #define SQLITE_CONFIG_PAGECACHE     7  /* void*, int sz, int N */
 #define SQLITE_CONFIG_HEAP          8  /* void*, int nByte, int min */
 #define SQLITE_CONFIG_MEMSTATUS     9  /* boolean */
 #define SQLITE_CONFIG_MUTEX        10  /* sqlite3_mutex_methods* */
 #define SQLITE_CONFIG_GETMUTEX     11  /* sqlite3_mutex_methods* */
 /* previously SQLITE_CONFIG_CHUNKALLOC 12 which is now unused. */ 
 #define SQLITE_CONFIG_LOOKASIDE    13  /* int int */
 #define SQLITE_CONFIG_PCACHE       14  /* no-op */
 #define SQLITE_CONFIG_GETPCACHE    15  /* no-op */
 #define SQLITE_CONFIG_LOG          16  /* xFunc, void* */
 #define SQLITE_CONFIG_URI          17  /* int */
 #define SQLITE_CONFIG_PCACHE2      18  /* sqlite3_pcache_methods2* */
 #define SQLITE_CONFIG_GETPCACHE2   19  /* sqlite3_pcache_methods2* */
 #define SQLITE_CONFIG_COVERING_INDEX_SCAN 20  /* int */
 #define SQLITE_CONFIG_SQLLOG       21  /* xSqllog, void* */
 #define SQLITE_CONFIG_MMAP_SIZE    22  /* sqlite3_int64, sqlite3_int64 */
 #define SQLITE_CONFIG_WIN32_HEAPSIZE      23  /* int nByte */
 #define SQLITE_CONFIG_PCACHE_HDRSZ        24  /* int *psz */
 #define SQLITE_CONFIG_PMASZ               25  /* unsigned int szPma */
 #define SQLITE_CONFIG_STMTJRNL_SPILL      26  /* int nByte */
 #define SQLITE_CONFIG_SMALL_MALLOC        27  /* boolean */
 
 /*
 ** CAPI3REF: Database Connection Configuration Options
 **
 ** These constants are the available integer configuration options that
 ** can be passed as the second argument to the [sqlite3_db_config()] interface.
 **
 ** New configuration options may be added in future releases of SQLite.
 ** Existing configuration options might be discontinued.  Applications
 ** should check the return code from [sqlite3_db_config()] to make sure that
 ** the call worked.  ^The [sqlite3_db_config()] interface will return a
 ** non-zero [error code] if a discontinued or unsupported configuration option
 ** is invoked.
 **
 ** <dl>
 ** <dt>SQLITE_DBCONFIG_LOOKASIDE</dt>
 ** <dd> ^This option takes three additional arguments that determine the 
 ** [lookaside memory allocator] configuration for the [database connection].
 ** ^The first argument (the third parameter to [sqlite3_db_config()] is a
 ** pointer to a memory buffer to use for lookaside memory.
 ** ^The first argument after the SQLITE_DBCONFIG_LOOKASIDE verb
 ** may be NULL in which case SQLite will allocate the
 ** lookaside buffer itself using [sqlite3_malloc()]. ^The second argument is the
 ** size of each lookaside buffer slot.  ^The third argument is the number of
 ** slots.  The size of the buffer in the first argument must be greater than
 ** or equal to the product of the second and third arguments.  The buffer
 ** must be aligned to an 8-byte boundary.  ^If the second argument to
 ** SQLITE_DBCONFIG_LOOKASIDE is not a multiple of 8, it is internally
 ** rounded down to the next smaller multiple of 8.  ^(The lookaside memory
 ** configuration for a database connection can only be changed when that
 ** connection is not currently using lookaside memory, or in other words
 ** when the "current value" returned by
 ** [sqlite3_db_status](D,[SQLITE_CONFIG_LOOKASIDE],...) is zero.
 ** Any attempt to change the lookaside memory configuration when lookaside
 ** memory is in use leaves the configuration unchanged and returns 
 ** [SQLITE_BUSY].)^</dd>
 **
 ** <dt>SQLITE_DBCONFIG_ENABLE_FKEY</dt>
 ** <dd> ^This option is used to enable or disable the enforcement of
 ** [foreign key constraints].  There should be two additional arguments.
 ** The first argument is an integer which is 0 to disable FK enforcement,
 ** positive to enable FK enforcement or negative to leave FK enforcement
 ** unchanged.  The second parameter is a pointer to an integer into which
 ** is written 0 or 1 to indicate whether FK enforcement is off or on
 ** following this call.  The second parameter may be a NULL pointer, in
 ** which case the FK enforcement setting is not reported back. </dd>
 **
 ** <dt>SQLITE_DBCONFIG_ENABLE_TRIGGER</dt>
 ** <dd> ^This option is used to enable or disable [CREATE TRIGGER | triggers].
 ** There should be two additional arguments.
 ** The first argument is an integer which is 0 to disable triggers,
 ** positive to enable triggers or negative to leave the setting unchanged.
 ** The second parameter is a pointer to an integer into which
 ** is written 0 or 1 to indicate whether triggers are disabled or enabled
 ** following this call.  The second parameter may be a NULL pointer, in
 ** which case the trigger setting is not reported back. </dd>
 **
 ** <dt>SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER</dt>
 ** <dd> ^This option is used to enable or disable the two-argument
 ** version of the [fts3_tokenizer()] function which is part of the
 ** [FTS3] full-text search engine extension.
 ** There should be two additional arguments.
 ** The first argument is an integer which is 0 to disable fts3_tokenizer() or
 ** positive to enable fts3_tokenizer() or negative to leave the setting
 ** unchanged.
 ** The second parameter is a pointer to an integer into which
 ** is written 0 or 1 to indicate whether fts3_tokenizer is disabled or enabled
 ** following this call.  The second parameter may be a NULL pointer, in
 ** which case the new setting is not reported back. </dd>
 **
 ** <dt>SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION</dt>
 ** <dd> ^This option is used to enable or disable the [sqlite3_load_extension()]
 ** interface independently of the [load_extension()] SQL function.
 ** The [sqlite3_enable_load_extension()] API enables or disables both the
 ** C-API [sqlite3_load_extension()] and the SQL function [load_extension()].
 ** There should be two additional arguments.
 ** When the first argument to this interface is 1, then only the C-API is
 ** enabled and the SQL function remains disabled.  If the first argument to
 ** this interface is 0, then both the C-API and the SQL function are disabled.
 ** If the first argument is -1, then no changes are made to state of either the
 ** C-API or the SQL function.
 ** The second parameter is a pointer to an integer into which
 ** is written 0 or 1 to indicate whether [sqlite3_load_extension()] interface
 ** is disabled or enabled following this call.  The second parameter may
 ** be a NULL pointer, in which case the new setting is not reported back.
 ** </dd>
 **
 ** <dt>SQLITE_DBCONFIG_MAINDBNAME</dt>
 ** <dd> ^This option is used to change the name of the "main" database
 ** schema.  ^The sole argument is a pointer to a constant UTF8 string
 ** which will become the new schema name in place of "main".  ^SQLite
 ** does not make a copy of the new main schema name string, so the application
 ** must ensure that the argument passed into this DBCONFIG option is unchanged
 ** until after the database connection closes.
 ** </dd>
 **
 ** <dt>SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE</dt>
 ** <dd> Usually, when a database in wal mode is closed or detached from a 
 ** database handle, SQLite checks if this will mean that there are now no 
 ** connections at all to the database. If so, it performs a checkpoint 
 ** operation before closing the connection. This option may be used to
 ** override this behaviour. The first parameter passed to this operation
 ** is an integer - non-zero to disable checkpoints-on-close, or zero (the
 ** default) to enable them. The second parameter is a pointer to an integer
 ** into which is written 0 or 1 to indicate whether checkpoints-on-close
 ** have been disabled - 0 if they are not disabled, 1 if they are.
 ** </dd>
 ** <dt>SQLITE_DBCONFIG_ENABLE_QPSG</dt>
 ** <dd>^(The SQLITE_DBCONFIG_ENABLE_QPSG option activates or deactivates
 ** the [query planner stability guarantee] (QPSG).  When the QPSG is active,
 ** a single SQL query statement will always use the same algorithm regardless
 ** of values of [bound parameters].)^ The QPSG disables some query optimizations
 ** that look at the values of bound parameters, which can make some queries
 ** slower.  But the QPSG has the advantage of more predictable behavior.  With
 ** the QPSG active, SQLite will always use the same query plan in the field as
 ** was used during testing in the lab.
 ** </dd>
 ** <dt>SQLITE_DBCONFIG_TRIGGER_EQP</dt>
 ** <dd> By default, the output of EXPLAIN QUERY PLAN commands does not 
 ** include output for any operations performed by trigger programs. This
 ** option is used to set or clear (the default) a flag that governs this
 ** behavior. The first parameter passed to this operation is an integer -
 ** non-zero to enable output for trigger programs, or zero to disable it.
 ** The second parameter is a pointer to an integer into which is written 
 ** 0 or 1 to indicate whether output-for-triggers has been disabled - 0 if 
 ** it is not disabled, 1 if it is.  
 ** </dd>
 ** </dl>
 */
 #define SQLITE_DBCONFIG_MAINDBNAME            1000 /* const char* */
 #define SQLITE_DBCONFIG_LOOKASIDE             1001 /* void* int int */
 #define SQLITE_DBCONFIG_ENABLE_FKEY           1002 /* int int* */
 #define SQLITE_DBCONFIG_ENABLE_TRIGGER        1003 /* int int* */
 #define SQLITE_DBCONFIG_ENABLE_FTS3_TOKENIZER 1004 /* int int* */
 #define SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION 1005 /* int int* */
 #define SQLITE_DBCONFIG_NO_CKPT_ON_CLOSE      1006 /* int int* */
 #define SQLITE_DBCONFIG_ENABLE_QPSG           1007 /* int int* */
 #define SQLITE_DBCONFIG_TRIGGER_EQP           1008 /* int int* */
 #define SQLITE_DBCONFIG_MAX                   1008 /* Largest DBCONFIG */
 
 /*
 ** CAPI3REF: Enable Or Disable Extended Result Codes
 ** METHOD: sqlite3
 **
 ** ^The sqlite3_extended_result_codes() routine enables or disables the
 ** [extended result codes] feature of SQLite. ^The extended result
 ** codes are disabled by default for historical compatibility.
 */
 SQLITE_API int sqlite3_extended_result_codes(sqlite3*, int onoff);
 
 /*
 ** CAPI3REF: Last Insert Rowid
 ** METHOD: sqlite3
 **
 ** ^Each entry in most SQLite tables (except for [WITHOUT ROWID] tables)
 ** has a unique 64-bit signed
 ** integer key called the [ROWID | "rowid"]. ^The rowid is always available
 ** as an undeclared column named ROWID, OID, or _ROWID_ as long as those
 ** names are not also used by explicitly declared columns. ^If
 ** the table has a column of type [INTEGER PRIMARY KEY] then that column
 ** is another alias for the rowid.
 **
 ** ^The sqlite3_last_insert_rowid(D) interface usually returns the [rowid] of
 ** the most recent successful [INSERT] into a rowid table or [virtual table]
 ** on database connection D. ^Inserts into [WITHOUT ROWID] tables are not
 ** recorded. ^If no successful [INSERT]s into rowid tables have ever occurred 
 ** on the database connection D, then sqlite3_last_insert_rowid(D) returns 
 ** zero.
 **
 ** As well as being set automatically as rows are inserted into database
 ** tables, the value returned by this function may be set explicitly by
 ** [sqlite3_set_last_insert_rowid()]
 **
 ** Some virtual table implementations may INSERT rows into rowid tables as
 ** part of committing a transaction (e.g. to flush data accumulated in memory
 ** to disk). In this case subsequent calls to this function return the rowid
 ** associated with these internal INSERT operations, which leads to 
 ** unintuitive results. Virtual table implementations that do write to rowid
 ** tables in this way can avoid this problem by restoring the original 
 ** rowid value using [sqlite3_set_last_insert_rowid()] before returning 
 ** control to the user.
 **
 ** ^(If an [INSERT] occurs within a trigger then this routine will 
 ** return the [rowid] of the inserted row as long as the trigger is 
 ** running. Once the trigger program ends, the value returned 
 ** by this routine reverts to what it was before the trigger was fired.)^
 **
 ** ^An [INSERT] that fails due to a constraint violation is not a
 ** successful [INSERT] and does not change the value returned by this
 ** routine.  ^Thus INSERT OR FAIL, INSERT OR IGNORE, INSERT OR ROLLBACK,
 ** and INSERT OR ABORT make no changes to the return value of this
 ** routine when their insertion fails.  ^(When INSERT OR REPLACE
 ** encounters a constraint violation, it does not fail.  The
 ** INSERT continues to completion after deleting rows that caused
 ** the constraint problem so INSERT OR REPLACE will always change
 ** the return value of this interface.)^
 **
 ** ^For the purposes of this routine, an [INSERT] is considered to
 ** be successful even if it is subsequently rolled back.
 **
 ** This function is accessible to SQL statements via the
 ** [last_insert_rowid() SQL function].
 **
 ** If a separate thread performs a new [INSERT] on the same
 ** database connection while the [sqlite3_last_insert_rowid()]
 ** function is running and thus changes the last insert [rowid],
 ** then the value returned by [sqlite3_last_insert_rowid()] is
 ** unpredictable and might not equal either the old or the new
 ** last insert [rowid].
 */
 SQLITE_API sqlite3_int64 sqlite3_last_insert_rowid(sqlite3*);
 
 /*
 ** CAPI3REF: Set the Last Insert Rowid value.
 ** METHOD: sqlite3
 **
 ** The sqlite3_set_last_insert_rowid(D, R) method allows the application to
 ** set the value returned by calling sqlite3_last_insert_rowid(D) to R 
 ** without inserting a row into the database.
 */
 SQLITE_API void sqlite3_set_last_insert_rowid(sqlite3*,sqlite3_int64);
 
 /*
 ** CAPI3REF: Count The Number Of Rows Modified
 ** METHOD: sqlite3
 **
 ** ^This function returns the number of rows modified, inserted or
 ** deleted by the most recently completed INSERT, UPDATE or DELETE
 ** statement on the database connection specified by the only parameter.
 ** ^Executing any other type of SQL statement does not modify the value
 ** returned by this function.
 **
 ** ^Only changes made directly by the INSERT, UPDATE or DELETE statement are
 ** considered - auxiliary changes caused by [CREATE TRIGGER | triggers], 
 ** [foreign key actions] or [REPLACE] constraint resolution are not counted.
 ** 
 ** Changes to a view that are intercepted by 
 ** [INSTEAD OF trigger | INSTEAD OF triggers] are not counted. ^The value 
 ** returned by sqlite3_changes() immediately after an INSERT, UPDATE or 
 ** DELETE statement run on a view is always zero. Only changes made to real 
 ** tables are counted.
 **
 ** Things are more complicated if the sqlite3_changes() function is
 ** executed while a trigger program is running. This may happen if the
 ** program uses the [changes() SQL function], or if some other callback
 ** function invokes sqlite3_changes() directly. Essentially:
 ** 
 ** <ul>
 **   <li> ^(Before entering a trigger program the value returned by
 **        sqlite3_changes() function is saved. After the trigger program 
 **        has finished, the original value is restored.)^
 ** 
 **   <li> ^(Within a trigger program each INSERT, UPDATE and DELETE 
 **        statement sets the value returned by sqlite3_changes() 
 **        upon completion as normal. Of course, this value will not include 
 **        any changes performed by sub-triggers, as the sqlite3_changes() 
 **        value will be saved and restored after each sub-trigger has run.)^
 ** </ul>
 ** 
 ** ^This means that if the changes() SQL function (or similar) is used
 ** by the first INSERT, UPDATE or DELETE statement within a trigger, it 
 ** returns the value as set when the calling statement began executing.
 ** ^If it is used by the second or subsequent such statement within a trigger 
 ** program, the value returned reflects the number of rows modified by the 
 ** previous INSERT, UPDATE or DELETE statement within the same trigger.
 **
 ** See also the [sqlite3_total_changes()] interface, the
 ** [count_changes pragma], and the [changes() SQL function].
 **
 ** If a separate thread makes changes on the same database connection
 ** while [sqlite3_changes()] is running then the value returned
 ** is unpredictable and not meaningful.
 */
 SQLITE_API int sqlite3_changes(sqlite3*);
 
 /*
 ** CAPI3REF: Total Number Of Rows Modified
 ** METHOD: sqlite3
 **
 ** ^This function returns the total number of rows inserted, modified or
 ** deleted by all [INSERT], [UPDATE] or [DELETE] statements completed
 ** since the database connection was opened, including those executed as
 ** part of trigger programs. ^Executing any other type of SQL statement
 ** does not affect the value returned by sqlite3_total_changes().
 ** 
 ** ^Changes made as part of [foreign key actions] are included in the
 ** count, but those made as part of REPLACE constraint resolution are
 ** not. ^Changes to a view that are intercepted by INSTEAD OF triggers 
 ** are not counted.
 ** 
 ** See also the [sqlite3_changes()] interface, the
 ** [count_changes pragma], and the [total_changes() SQL function].
 **
 ** If a separate thread makes changes on the same database connection
 ** while [sqlite3_total_changes()] is running then the value
 ** returned is unpredictable and not meaningful.
 */
 SQLITE_API int sqlite3_total_changes(sqlite3*);
 
 /*
 ** CAPI3REF: Interrupt A Long-Running Query
 ** METHOD: sqlite3
 **
 ** ^This function causes any pending database operation to abort and
 ** return at its earliest opportunity. This routine is typically
 ** called in response to a user action such as pressing "Cancel"
 ** or Ctrl-C where the user wants a long query operation to halt
 ** immediately.
 **
 ** ^It is safe to call this routine from a thread different from the
 ** thread that is currently running the database operation.  But it
 ** is not safe to call this routine with a [database connection] that
 ** is closed or might close before sqlite3_interrupt() returns.
 **
 ** ^If an SQL operation is very nearly finished at the time when
 ** sqlite3_interrupt() is called, then it might not have an opportunity
 ** to be interrupted and might continue to completion.
 **
 ** ^An SQL operation that is interrupted will return [SQLITE_INTERRUPT].
 ** ^If the interrupted SQL operation is an INSERT, UPDATE, or DELETE
 ** that is inside an explicit transaction, then the entire transaction
 ** will be rolled back automatically.
 **
 ** ^The sqlite3_interrupt(D) call is in effect until all currently running
 ** SQL statements on [database connection] D complete.  ^Any new SQL statements
 ** that are started after the sqlite3_interrupt() call and before the 
 ** running statements reaches zero are interrupted as if they had been
 ** running prior to the sqlite3_interrupt() call.  ^New SQL statements
 ** that are started after the running statement count reaches zero are
 ** not effected by the sqlite3_interrupt().
 ** ^A call to sqlite3_interrupt(D) that occurs when there are no running
 ** SQL statements is a no-op and has no effect on SQL statements
 ** that are started after the sqlite3_interrupt() call returns.
 */
 SQLITE_API void sqlite3_interrupt(sqlite3*);
 
 /*
 ** CAPI3REF: Determine If An SQL Statement Is Complete
 **
 ** These routines are useful during command-line input to determine if the
 ** currently entered text seems to form a complete SQL statement or
 ** if additional input is needed before sending the text into
 ** SQLite for parsing.  ^These routines return 1 if the input string
 ** appears to be a complete SQL statement.  ^A statement is judged to be
 ** complete if it ends with a semicolon token and is not a prefix of a
 ** well-formed CREATE TRIGGER statement.  ^Semicolons that are embedded within
 ** string literals or quoted identifier names or comments are not
 ** independent tokens (they are part of the token in which they are
 ** embedded) and thus do not count as a statement terminator.  ^Whitespace
 ** and comments that follow the final semicolon are ignored.
 **
 ** ^These routines return 0 if the statement is incomplete.  ^If a
 ** memory allocation fails, then SQLITE_NOMEM is returned.
 **
 ** ^These routines do not parse the SQL statements thus
 ** will not detect syntactically incorrect SQL.
 **
 ** ^(If SQLite has not been initialized using [sqlite3_initialize()] prior 
 ** to invoking sqlite3_complete16() then sqlite3_initialize() is invoked
 ** automatically by sqlite3_complete16().  If that initialization fails,
 ** then the return value from sqlite3_complete16() will be non-zero
 ** regardless of whether or not the input SQL is complete.)^
 **
 ** The input to [sqlite3_complete()] must be a zero-terminated
 ** UTF-8 string.
 **
 ** The input to [sqlite3_complete16()] must be a zero-terminated
 ** UTF-16 string in native byte order.
 */
 SQLITE_API int sqlite3_complete(const char *sql);
 SQLITE_API int sqlite3_complete16(const void *sql);
 
 /*
 ** CAPI3REF: Register A Callback To Handle SQLITE_BUSY Errors
 ** KEYWORDS: {busy-handler callback} {busy handler}
 ** METHOD: sqlite3
 **
 ** ^The sqlite3_busy_handler(D,X,P) routine sets a callback function X
 ** that might be invoked with argument P whenever
 ** an attempt is made to access a database table associated with
 ** [database connection] D when another thread
 ** or process has the table locked.
 ** The sqlite3_busy_handler() interface is used to implement
 ** [sqlite3_busy_timeout()] and [PRAGMA busy_timeout].
 **
 ** ^If the busy callback is NULL, then [SQLITE_BUSY]
 ** is returned immediately upon encountering the lock.  ^If the busy callback
 ** is not NULL, then the callback might be invoked with two arguments.
 **
 ** ^The first argument to the busy handler is a copy of the void* pointer which
 ** is the third argument to sqlite3_busy_handler().  ^The second argument to
 ** the busy handler callback is the number of times that the busy handler has
 ** been invoked previously for the same locking event.  ^If the
 ** busy callback returns 0, then no additional attempts are made to
 ** access the database and [SQLITE_BUSY] is returned
 ** to the application.
 ** ^If the callback returns non-zero, then another attempt
 ** is made to access the database and the cycle repeats.
 **
 ** The presence of a busy handler does not guarantee that it will be invoked
 ** when there is lock contention. ^If SQLite determines that invoking the busy
 ** handler could result in a deadlock, it will go ahead and return [SQLITE_BUSY]
 ** to the application instead of invoking the 
 ** busy handler.
 ** Consider a scenario where one process is holding a read lock that
 ** it is trying to promote to a reserved lock and
 ** a second process is holding a reserved lock that it is trying
 ** to promote to an exclusive lock.  The first process cannot proceed
 ** because it is blocked by the second and the second process cannot
 ** proceed because it is blocked by the first.  If both processes
 ** invoke the busy handlers, neither will make any progress.  Therefore,
 ** SQLite returns [SQLITE_BUSY] for the first process, hoping that this
 ** will induce the first process to release its read lock and allow
 ** the second process to proceed.
 **
 ** ^The default busy callback is NULL.
 **
 ** ^(There can only be a single busy handler defined for each
 ** [database connection].  Setting a new busy handler clears any
 ** previously set handler.)^  ^Note that calling [sqlite3_busy_timeout()]
 ** or evaluating [PRAGMA busy_timeout=N] will change the
 ** busy handler and thus clear any previously set busy handler.
 **
 ** The busy callback should not take any actions which modify the
 ** database connection that invoked the busy handler.  In other words,
 ** the busy handler is not reentrant.  Any such actions
 ** result in undefined behavior.
 ** 
 ** A busy handler must not close the database connection
 ** or [prepared statement] that invoked the busy handler.
 */
 SQLITE_API int sqlite3_busy_handler(sqlite3*,int(*)(void*,int),void*);
 
 /*
 ** CAPI3REF: Set A Busy Timeout
 ** METHOD: sqlite3
 **
 ** ^This routine sets a [sqlite3_busy_handler | busy handler] that sleeps
 ** for a specified amount of time when a table is locked.  ^The handler
 ** will sleep multiple times until at least "ms" milliseconds of sleeping
 ** have accumulated.  ^After at least "ms" milliseconds of sleeping,
 ** the handler returns 0 which causes [sqlite3_step()] to return
 ** [SQLITE_BUSY].
 **
 ** ^Calling this routine with an argument less than or equal to zero
 ** turns off all busy handlers.
 **
 ** ^(There can only be a single busy handler for a particular
 ** [database connection] at any given moment.  If another busy handler
 ** was defined  (using [sqlite3_busy_handler()]) prior to calling
 ** this routine, that other busy handler is cleared.)^
 **
 ** See also:  [PRAGMA busy_timeout]
 */
 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);
 
 /*
 ** CAPI3REF: Convenience Routines For Running Queries
 ** METHOD: sqlite3
 **
 ** This is a legacy interface that is preserved for backwards compatibility.
 ** Use of this interface is not recommended.
 **
 ** Definition: A <b>result table</b> is memory data structure created by the
 ** [sqlite3_get_table()] interface.  A result table records the
 ** complete query results from one or more queries.
 **
 ** The table conceptually has a number of rows and columns.  But
 ** these numbers are not part of the result table itself.  These
 ** numbers are obtained separately.  Let N be the number of rows
 ** and M be the number of columns.
 **
 ** A result table is an array of pointers to zero-terminated UTF-8 strings.
 ** There are (N+1)*M elements in the array.  The first M pointers point
 ** to zero-terminated strings that  contain the names of the columns.
 ** The remaining entries all point to query results.  NULL values result
 ** in NULL pointers.  All other values are in their UTF-8 zero-terminated
 ** string representation as returned by [sqlite3_column_text()].
 **
 ** A result table might consist of one or more memory allocations.
 ** It is not safe to pass a result table directly to [sqlite3_free()].
 ** A result table should be deallocated using [sqlite3_free_table()].
 **
 ** ^(As an example of the result table format, suppose a query result
 ** is as follows:
 **
 ** <blockquote><pre>
 **        Name        | Age
 **        -----------------------
 **        Alice       | 43
 **        Bob         | 28
 **        Cindy       | 21
 ** </pre></blockquote>
 **
 ** There are two column (M==2) and three rows (N==3).  Thus the
 ** result table has 8 entries.  Suppose the result table is stored
 ** in an array names azResult.  Then azResult holds this content:
 **
 ** <blockquote><pre>
 **        azResult&#91;0] = "Name";
 **        azResult&#91;1] = "Age";
 **        azResult&#91;2] = "Alice";
 **        azResult&#91;3] = "43";
 **        azResult&#91;4] = "Bob";
 **        azResult&#91;5] = "28";
 **        azResult&#91;6] = "Cindy";
 **        azResult&#91;7] = "21";
 ** </pre></blockquote>)^
 **
 ** ^The sqlite3_get_table() function evaluates one or more
 ** semicolon-separated SQL statements in the zero-terminated UTF-8
 ** string of its 2nd parameter and returns a result table to the
 ** pointer given in its 3rd parameter.
 **
 ** After the application has finished with the result from sqlite3_get_table(),
 ** it must pass the result table pointer to sqlite3_free_table() in order to
 ** release the memory that was malloced.  Because of the way the
 ** [sqlite3_malloc()] happens within sqlite3_get_table(), the calling
 ** function must not try to call [sqlite3_free()] directly.  Only
 ** [sqlite3_free_table()] is able to release the memory properly and safely.
 **
 ** The sqlite3_get_table() interface is implemented as a wrapper around
 ** [sqlite3_exec()].  The sqlite3_get_table() routine does not have access
 ** to any internal data structures of SQLite.  It uses only the public
 ** interface defined here.  As a consequence, errors that occur in the
 ** wrapper layer outside of the internal [sqlite3_exec()] call are not
 ** reflected in subsequent calls to [sqlite3_errcode()] or
 ** [sqlite3_errmsg()].
 */
 SQLITE_API int sqlite3_get_table(
   sqlite3 *db,          /* An open database */
   const char *zSql,     /* SQL to be evaluated */
   char ***pazResult,    /* Results of the query */
   int *pnRow,           /* Number of result rows written here */
   int *pnColumn,        /* Number of result columns written here */
   char **pzErrmsg       /* Error msg written here */
 );
 SQLITE_API void sqlite3_free_table(char **result);
 
 /*
 ** CAPI3REF: Formatted String Printing Functions
 **
 ** These routines are work-alikes of the "printf()" family of functions
 ** from the standard C library.
 ** These routines understand most of the common K&R formatting options,
 ** plus some additional non-standard formats, detailed below.
 ** Note that some of the more obscure formatting options from recent
 ** C-library standards are omitted from this implementation.
 **
 ** ^The sqlite3_mprintf() and sqlite3_vmprintf() routines write their
 ** results into memory obtained from [sqlite3_malloc()].
 ** The strings returned by these two routines should be
 ** released by [sqlite3_free()].  ^Both routines return a
 ** NULL pointer if [sqlite3_malloc()] is unable to allocate enough
 ** memory to hold the resulting string.
 **
 ** ^(The sqlite3_snprintf() routine is similar to "snprintf()" from
 ** the standard C library.  The result is written into the
 ** buffer supplied as the second parameter whose size is given by
 ** the first parameter. Note that the order of the
 ** first two parameters is reversed from snprintf().)^  This is an
 ** historical accident that cannot be fixed without breaking
 ** backwards compatibility.  ^(Note also that sqlite3_snprintf()
 ** returns a pointer to its buffer instead of the number of
 ** characters actually written into the buffer.)^  We admit that
 ** the number of characters written would be a more useful return
 ** value but we cannot change the implementation of sqlite3_snprintf()
 ** now without breaking compatibility.
 **
 ** ^As long as the buffer size is greater than zero, sqlite3_snprintf()
 ** guarantees that the buffer is always zero-terminated.  ^The first
 ** parameter "n" is the total size of the buffer, including space for
 ** the zero terminator.  So the longest string that can be completely
 ** written will be n-1 characters.
 **
 ** ^The sqlite3_vsnprintf() routine is a varargs version of sqlite3_snprintf().
 **
 ** These routines all implement some additional formatting
 ** options that are useful for constructing SQL statements.
 ** All of the usual printf() formatting options apply.  In addition, there
 ** is are "%q", "%Q", "%w" and "%z" options.
 **
 ** ^(The %q option works like %s in that it substitutes a nul-terminated
 ** string from the argument list.  But %q also doubles every '\'' character.
 ** %q is designed for use inside a string literal.)^  By doubling each '\''
 ** character it escapes that character and allows it to be inserted into
 ** the string.
 **
 ** For example, assume the string variable zText contains text as follows:
 **
 ** <blockquote><pre>
 **  char *zText = "It's a happy day!";
 ** </pre></blockquote>
 **
 ** One can use this text in an SQL statement as follows:
 **
 ** <blockquote><pre>
 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES('%q')", zText);
 **  sqlite3_exec(db, zSQL, 0, 0, 0);
 **  sqlite3_free(zSQL);
 ** </pre></blockquote>
 **
 ** Because the %q format string is used, the '\'' character in zText
 ** is escaped and the SQL generated is as follows:
 **
 ** <blockquote><pre>
 **  INSERT INTO table1 VALUES('It''s a happy day!')
 ** </pre></blockquote>
 **
 ** This is correct.  Had we used %s instead of %q, the generated SQL
 ** would have looked like this:
 **
 ** <blockquote><pre>
 **  INSERT INTO table1 VALUES('It's a happy day!');
 ** </pre></blockquote>
 **
 ** This second example is an SQL syntax error.  As a general rule you should
 ** always use %q instead of %s when inserting text into a string literal.
 **
 ** ^(The %Q option works like %q except it also adds single quotes around
 ** the outside of the total string.  Additionally, if the parameter in the
 ** argument list is a NULL pointer, %Q substitutes the text "NULL" (without
 ** single quotes).)^  So, for example, one could say:
 **
 ** <blockquote><pre>
 **  char *zSQL = sqlite3_mprintf("INSERT INTO table VALUES(%Q)", zText);
 **  sqlite3_exec(db, zSQL, 0, 0, 0);
 **  sqlite3_free(zSQL);
 ** </pre></blockquote>
 **
 ** The code above will render a correct SQL statement in the zSQL
 ** variable even if the zText variable is a NULL pointer.
 **
 ** ^(The "%w" formatting option is like "%q" except that it expects to
 ** be contained within double-quotes instead of single quotes, and it
 ** escapes the double-quote character instead of the single-quote
 ** character.)^  The "%w" formatting option is intended for safely inserting
 ** table and column names into a constructed SQL statement.
 **
 ** ^(The "%z" formatting option works like "%s" but with the
 ** addition that after the string has been read and copied into
 ** the result, [sqlite3_free()] is called on the input string.)^
 */
 SQLITE_API char *sqlite3_mprintf(const char*,...);
 SQLITE_API char *sqlite3_vmprintf(const char*, va_list);
 SQLITE_API char *sqlite3_snprintf(int,char*,const char*, ...);
 SQLITE_API char *sqlite3_vsnprintf(int,char*,const char*, va_list);
 
 /*
 ** CAPI3REF: Memory Allocation Subsystem
 **
 ** The SQLite core uses these three routines for all of its own
 ** internal memory allocation needs. "Core" in the previous sentence
 ** does not include operating-system specific VFS implementation.  The
 ** Windows VFS uses native malloc() and free() for some operations.
 **
 ** ^The sqlite3_malloc() routine returns a pointer to a block
 ** of memory at least N bytes in length, where N is the parameter.
 ** ^If sqlite3_malloc() is unable to obtain sufficient free
 ** memory, it returns a NULL pointer.  ^If the parameter N to
 ** sqlite3_malloc() is zero or negative then sqlite3_malloc() returns
 ** a NULL pointer.
 **
 ** ^The sqlite3_malloc64(N) routine works just like
 ** sqlite3_malloc(N) except that N is an unsigned 64-bit integer instead
 ** of a signed 32-bit integer.
 **
 ** ^Calling sqlite3_free() with a pointer previously returned
 ** by sqlite3_malloc() or sqlite3_realloc() releases that memory so
 ** that it might be reused.  ^The sqlite3_free() routine is
 ** a no-op if is called with a NULL pointer.  Passing a NULL pointer
 ** to sqlite3_free() is harmless.  After being freed, memory
 ** should neither be read nor written.  Even reading previously freed
 ** memory might result in a segmentation fault or other severe error.
 ** Memory corruption, a segmentation fault, or other severe error
 ** might result if sqlite3_free() is called with a non-NULL pointer that
 ** was not obtained from sqlite3_malloc() or sqlite3_realloc().
 **
 ** ^The sqlite3_realloc(X,N) interface attempts to resize a
 ** prior memory allocation X to be at least N bytes.
 ** ^If the X parameter to sqlite3_realloc(X,N)
 ** is a NULL pointer then its behavior is identical to calling
 ** sqlite3_malloc(N).
 ** ^If the N parameter to sqlite3_realloc(X,N) is zero or
 ** negative then the behavior is exactly the same as calling
 ** sqlite3_free(X).
 ** ^sqlite3_realloc(X,N) returns a pointer to a memory allocation
 ** of at least N bytes in size or NULL if insufficient memory is available.
 ** ^If M is the size of the prior allocation, then min(N,M) bytes
 ** of the prior allocation are copied into the beginning of buffer returned
 ** by sqlite3_realloc(X,N) and the prior allocation is freed.
 ** ^If sqlite3_realloc(X,N) returns NULL and N is positive, then the
 ** prior allocation is not freed.
 **
 ** ^The sqlite3_realloc64(X,N) interfaces works the same as
 ** sqlite3_realloc(X,N) except that N is a 64-bit unsigned integer instead
 ** of a 32-bit signed integer.
 **
 ** ^If X is a memory allocation previously obtained from sqlite3_malloc(),
 ** sqlite3_malloc64(), sqlite3_realloc(), or sqlite3_realloc64(), then
 ** sqlite3_msize(X) returns the size of that memory allocation in bytes.
 ** ^The value returned by sqlite3_msize(X) might be larger than the number
 ** of bytes requested when X was allocated.  ^If X is a NULL pointer then
 ** sqlite3_msize(X) returns zero.  If X points to something that is not
 ** the beginning of memory allocation, or if it points to a formerly
 ** valid memory allocation that has now been freed, then the behavior
 ** of sqlite3_msize(X) is undefined and possibly harmful.
 **
 ** ^The memory returned by sqlite3_malloc(), sqlite3_realloc(),
 ** sqlite3_malloc64(), and sqlite3_realloc64()
 ** is always aligned to at least an 8 byte boundary, or to a
 ** 4 byte boundary if the [SQLITE_4_BYTE_ALIGNED_MALLOC] compile-time
 ** option is used.
 **
 ** In SQLite version 3.5.0 and 3.5.1, it was possible to define
 ** the SQLITE_OMIT_MEMORY_ALLOCATION which would cause the built-in
 ** implementation of these routines to be omitted.  That capability
 ** is no longer provided.  Only built-in memory allocators can be used.
 **
 ** Prior to SQLite version 3.7.10, the Windows OS interface layer called
 ** the system malloc() and free() directly when converting
 ** filenames between the UTF-8 encoding used by SQLite
 ** and whatever filename encoding is used by the particular Windows
 ** installation.  Memory allocation errors were detected, but
 ** they were reported back as [SQLITE_CANTOPEN] or
 ** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
 **
 ** The pointer arguments to [sqlite3_free()] and [sqlite3_realloc()]
 ** must be either NULL or else pointers obtained from a prior
 ** invocation of [sqlite3_malloc()] or [sqlite3_realloc()] that have
 ** not yet been released.
 **
 ** The application must not read or write any part of
 ** a block of memory after it has been released using
 ** [sqlite3_free()] or [sqlite3_realloc()].
 */
 SQLITE_API void *sqlite3_malloc(int);
 SQLITE_API void *sqlite3_malloc64(sqlite3_uint64);
 SQLITE_API void *sqlite3_realloc(void*, int);
 SQLITE_API void *sqlite3_realloc64(void*, sqlite3_uint64);
 SQLITE_API void sqlite3_free(void*);
 SQLITE_API sqlite3_uint64 sqlite3_msize(void*);
 
 /*
 ** CAPI3REF: Memory Allocator Statistics
 **
 ** SQLite provides these two interfaces for reporting on the status
 ** of the [sqlite3_malloc()], [sqlite3_free()], and [sqlite3_realloc()]
 ** routines, which form the built-in memory allocation subsystem.
 **
 ** ^The [sqlite3_memory_used()] routine returns the number of bytes
 ** of memory currently outstanding (malloced but not freed).
 ** ^The [sqlite3_memory_highwater()] routine returns the maximum
 ** value of [sqlite3_memory_used()] since the high-water mark
 ** was last reset.  ^The values returned by [sqlite3_memory_used()] and
 ** [sqlite3_memory_highwater()] include any overhead
 ** added by SQLite in its implementation of [sqlite3_malloc()],
 ** but not overhead added by the any underlying system library
 ** routines that [sqlite3_malloc()] may call.
 **
 ** ^The memory high-water mark is reset to the current value of
 ** [sqlite3_memory_used()] if and only if the parameter to
 ** [sqlite3_memory_highwater()] is true.  ^The value returned
 ** by [sqlite3_memory_highwater(1)] is the high-water mark
 ** prior to the reset.
 */
 SQLITE_API sqlite3_int64 sqlite3_memory_used(void);
 SQLITE_API sqlite3_int64 sqlite3_memory_highwater(int resetFlag);
 
 /*
 ** CAPI3REF: Pseudo-Random Number Generator
 **
 ** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
 ** select random [ROWID | ROWIDs] when inserting new records into a table that
 ** already uses the largest possible [ROWID].  The PRNG is also used for
 ** the build-in random() and randomblob() SQL functions.  This interface allows
 ** applications to access the same PRNG for other purposes.
 **
 ** ^A call to this routine stores N bytes of randomness into buffer P.
 ** ^The P parameter can be a NULL pointer.
 **
 ** ^If this routine has not been previously called or if the previous
 ** call had N less than one or a NULL pointer for P, then the PRNG is
 ** seeded using randomness obtained from the xRandomness method of
 ** the default [sqlite3_vfs] object.
 ** ^If the previous call to this routine had an N of 1 or more and a
 ** non-NULL P then the pseudo-randomness is generated
 ** internally and without recourse to the [sqlite3_vfs] xRandomness
 ** method.
 */
 SQLITE_API void sqlite3_randomness(int N, void *P);
 
 /*
 ** CAPI3REF: Compile-Time Authorization Callbacks
 ** METHOD: sqlite3
 ** KEYWORDS: {authorizer callback}
 **
 ** ^This routine registers an authorizer callback with a particular
 ** [database connection], supplied in the first argument.
 ** ^The authorizer callback is invoked as SQL statements are being compiled
 ** by [sqlite3_prepare()] or its variants [sqlite3_prepare_v2()],
 ** [sqlite3_prepare_v3()], [sqlite3_prepare16()], [sqlite3_prepare16_v2()],
 ** and [sqlite3_prepare16_v3()].  ^At various
 ** points during the compilation process, as logic is being created
 ** to perform various actions, the authorizer callback is invoked to
 ** see if those actions are allowed.  ^The authorizer callback should
 ** return [SQLITE_OK] to allow the action, [SQLITE_IGNORE] to disallow the
 ** specific action but allow the SQL statement to continue to be
 ** compiled, or [SQLITE_DENY] to cause the entire SQL statement to be
 ** rejected with an error.  ^If the authorizer callback returns
 ** any value other than [SQLITE_IGNORE], [SQLITE_OK], or [SQLITE_DENY]
 ** then the [sqlite3_prepare_v2()] or equivalent call that triggered
 ** the authorizer will fail with an error message.
 **
 ** When the callback returns [SQLITE_OK], that means the operation
 ** requested is ok.  ^When the callback returns [SQLITE_DENY], the
 ** [sqlite3_prepare_v2()] or equivalent call that triggered the
 ** authorizer will fail with an error message explaining that
 ** access is denied. 
 **
 ** ^The first parameter to the authorizer callback is a copy of the third
 ** parameter to the sqlite3_set_authorizer() interface. ^The second parameter
 ** to the callback is an integer [SQLITE_COPY | action code] that specifies
 ** the particular action to be authorized. ^The third through sixth parameters
 ** to the callback are either NULL pointers or zero-terminated strings
 ** that contain additional details about the action to be authorized.
 ** Applications must always be prepared to encounter a NULL pointer in any
 ** of the third through the sixth parameters of the authorization callback.
 **
 ** ^If the action code is [SQLITE_READ]
 ** and the callback returns [SQLITE_IGNORE] then the
 ** [prepared statement] statement is constructed to substitute
 ** a NULL value in place of the table column that would have
 ** been read if [SQLITE_OK] had been returned.  The [SQLITE_IGNORE]
 ** return can be used to deny an untrusted user access to individual
 ** columns of a table.
 ** ^When a table is referenced by a [SELECT] but no column values are
 ** extracted from that table (for example in a query like
 ** "SELECT count(*) FROM tab") then the [SQLITE_READ] authorizer callback
 ** is invoked once for that table with a column name that is an empty string.
 ** ^If the action code is [SQLITE_DELETE] and the callback returns
 ** [SQLITE_IGNORE] then the [DELETE] operation proceeds but the
 ** [truncate optimization] is disabled and all rows are deleted individually.
 **
 ** An authorizer is used when [sqlite3_prepare | preparing]
 ** SQL statements from an untrusted source, to ensure that the SQL statements
 ** do not try to access data they are not allowed to see, or that they do not
 ** try to execute malicious statements that damage the database.  For
 ** example, an application may allow a user to enter arbitrary
 ** SQL queries for evaluation by a database.  But the application does
 ** not want the user to be able to make arbitrary changes to the
 ** database.  An authorizer could then be put in place while the
 ** user-entered SQL is being [sqlite3_prepare | prepared] that
 ** disallows everything except [SELECT] statements.
 **
 ** Applications that need to process SQL from untrusted sources
 ** might also consider lowering resource limits using [sqlite3_limit()]
 ** and limiting database size using the [max_page_count] [PRAGMA]
 ** in addition to using an authorizer.
 **
 ** ^(Only a single authorizer can be in place on a database connection
 ** at a time.  Each call to sqlite3_set_authorizer overrides the
 ** previous call.)^  ^Disable the authorizer by installing a NULL callback.
 ** The authorizer is disabled by default.
 **
 ** The authorizer callback must not do anything that will modify
 ** the database connection that invoked the authorizer callback.
 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
 ** database connections for the meaning of "modify" in this paragraph.
 **
 ** ^When [sqlite3_prepare_v2()] is used to prepare a statement, the
 ** statement might be re-prepared during [sqlite3_step()] due to a 
 ** schema change.  Hence, the application should ensure that the
 ** correct authorizer callback remains in place during the [sqlite3_step()].
 **
 ** ^Note that the authorizer callback is invoked only during
 ** [sqlite3_prepare()] or its variants.  Authorization is not
 ** performed during statement evaluation in [sqlite3_step()], unless
 ** as stated in the previous paragraph, sqlite3_step() invokes
 ** sqlite3_prepare_v2() to reprepare a statement after a schema change.
 */
 SQLITE_API int sqlite3_set_authorizer(
   sqlite3*,
   int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
   void *pUserData
 );
 
 /*
 ** CAPI3REF: Authorizer Return Codes
 **
 ** The [sqlite3_set_authorizer | authorizer callback function] must
 ** return either [SQLITE_OK] or one of these two constants in order
 ** to signal SQLite whether or not the action is permitted.  See the
 ** [sqlite3_set_authorizer | authorizer documentation] for additional
 ** information.
 **
 ** Note that SQLITE_IGNORE is also used as a [conflict resolution mode]
 ** returned from the [sqlite3_vtab_on_conflict()] interface.
 */
 #define SQLITE_DENY   1   /* Abort the SQL statement with an error */
 #define SQLITE_IGNORE 2   /* Don't allow access, but don't generate an error */
 
 /*
 ** CAPI3REF: Authorizer Action Codes
 **
 ** The [sqlite3_set_authorizer()] interface registers a callback function
 ** that is invoked to authorize certain SQL statement actions.  The
 ** second parameter to the callback is an integer code that specifies
 ** what action is being authorized.  These are the integer action codes that
 ** the authorizer callback may be passed.
 **
 ** These action code values signify what kind of operation is to be
 ** authorized.  The 3rd and 4th parameters to the authorization
 ** callback function will be parameters or NULL depending on which of these
 ** codes is used as the second parameter.  ^(The 5th parameter to the
 ** authorizer callback is the name of the database ("main", "temp",
 ** etc.) if applicable.)^  ^The 6th parameter to the authorizer callback
 ** is the name of the inner-most trigger or view that is responsible for
 ** the access attempt or NULL if this access attempt is directly from
 ** top-level SQL code.
 */
 /******************************************* 3rd ************ 4th ***********/
 #define SQLITE_CREATE_INDEX          1   /* Index Name      Table Name      */
 #define SQLITE_CREATE_TABLE          2   /* Table Name      NULL            */
 #define SQLITE_CREATE_TEMP_INDEX     3   /* Index Name      Table Name      */
 #define SQLITE_CREATE_TEMP_TABLE     4   /* Table Name      NULL            */
 #define SQLITE_CREATE_TEMP_TRIGGER   5   /* Trigger Name    Table Name      */
 #define SQLITE_CREATE_TEMP_VIEW      6   /* View Name       NULL            */
 #define SQLITE_CREATE_TRIGGER        7   /* Trigger Name    Table Name      */
 #define SQLITE_CREATE_VIEW           8   /* View Name       NULL            */
 #define SQLITE_DELETE                9   /* Table Name      NULL            */
 #define SQLITE_DROP_INDEX           10   /* Index Name      Table Name      */
 #define SQLITE_DROP_TABLE           11   /* Table Name      NULL            */
 #define SQLITE_DROP_TEMP_INDEX      12   /* Index Name      Table Name      */
 #define SQLITE_DROP_TEMP_TABLE      13   /* Table Name      NULL            */
 #define SQLITE_DROP_TEMP_TRIGGER    14   /* Trigger Name    Table Name      */
 #define SQLITE_DROP_TEMP_VIEW       15   /* View Name       NULL            */
 #define SQLITE_DROP_TRIGGER         16   /* Trigger Name    Table Name      */
 #define SQLITE_DROP_VIEW            17   /* View Name       NULL            */
 #define SQLITE_INSERT               18   /* Table Name      NULL            */
 #define SQLITE_PRAGMA               19   /* Pragma Name     1st arg or NULL */
 #define SQLITE_READ                 20   /* Table Name      Column Name     */
 #define SQLITE_SELECT               21   /* NULL            NULL            */
 #define SQLITE_TRANSACTION          22   /* Operation       NULL            */
 #define SQLITE_UPDATE               23   /* Table Name      Column Name     */
 #define SQLITE_ATTACH               24   /* Filename        NULL            */
 #define SQLITE_DETACH               25   /* Database Name   NULL            */
 #define SQLITE_ALTER_TABLE          26   /* Database Name   Table Name      */
 #define SQLITE_REINDEX              27   /* Index Name      NULL            */
 #define SQLITE_ANALYZE              28   /* Table Name      NULL            */
 #define SQLITE_CREATE_VTABLE        29   /* Table Name      Module Name     */
 #define SQLITE_DROP_VTABLE          30   /* Table Name      Module Name     */
 #define SQLITE_FUNCTION             31   /* NULL            Function Name   */
 #define SQLITE_SAVEPOINT            32   /* Operation       Savepoint Name  */
 #define SQLITE_COPY                  0   /* No longer used */
 #define SQLITE_RECURSIVE            33   /* NULL            NULL            */
 
 /*
 ** CAPI3REF: Tracing And Profiling Functions
 ** METHOD: sqlite3
 **
 ** These routines are deprecated. Use the [sqlite3_trace_v2()] interface
 ** instead of the routines described here.
 **
 ** These routines register callback functions that can be used for
 ** tracing and profiling the execution of SQL statements.
 **
 ** ^The callback function registered by sqlite3_trace() is invoked at
 ** various times when an SQL statement is being run by [sqlite3_step()].
 ** ^The sqlite3_trace() callback is invoked with a UTF-8 rendering of the
 ** SQL statement text as the statement first begins executing.
 ** ^(Additional sqlite3_trace() callbacks might occur
 ** as each triggered subprogram is entered.  The callbacks for triggers
 ** contain a UTF-8 SQL comment that identifies the trigger.)^
 **
 ** The [SQLITE_TRACE_SIZE_LIMIT] compile-time option can be used to limit
 ** the length of [bound parameter] expansion in the output of sqlite3_trace().
 **
 ** ^The callback function registered by sqlite3_profile() is invoked
 ** as each SQL statement finishes.  ^The profile callback contains
 ** the original statement text and an estimate of wall-clock time
 ** of how long that statement took to run.  ^The profile callback
 ** time is in units of nanoseconds, however the current implementation
 ** is only capable of millisecond resolution so the six least significant
 ** digits in the time are meaningless.  Future versions of SQLite
 ** might provide greater resolution on the profiler callback.  The
 ** sqlite3_profile() function is considered experimental and is
 ** subject to change in future versions of SQLite.
 */
 SQLITE_API SQLITE_DEPRECATED void *sqlite3_trace(sqlite3*,
    void(*xTrace)(void*,const char*), void*);
 SQLITE_API SQLITE_DEPRECATED void *sqlite3_profile(sqlite3*,
    void(*xProfile)(void*,const char*,sqlite3_uint64), void*);
 
 /*
 ** CAPI3REF: SQL Trace Event Codes
 ** KEYWORDS: SQLITE_TRACE
 **
 ** These constants identify classes of events that can be monitored
 ** using the [sqlite3_trace_v2()] tracing logic.  The M argument
 ** to [sqlite3_trace_v2(D,M,X,P)] is an OR-ed combination of one or more of
 ** the following constants.  ^The first argument to the trace callback
 ** is one of the following constants.
 **
 ** New tracing constants may be added in future releases.
 **
 ** ^A trace callback has four arguments: xCallback(T,C,P,X).
 ** ^The T argument is one of the integer type codes above.
 ** ^The C argument is a copy of the context pointer passed in as the
 ** fourth argument to [sqlite3_trace_v2()].
 ** The P and X arguments are pointers whose meanings depend on T.
 **
 ** <dl>
 ** [[SQLITE_TRACE_STMT]] <dt>SQLITE_TRACE_STMT</dt>
 ** <dd>^An SQLITE_TRACE_STMT callback is invoked when a prepared statement
 ** first begins running and possibly at other times during the
 ** execution of the prepared statement, such as at the start of each
 ** trigger subprogram. ^The P argument is a pointer to the
 ** [prepared statement]. ^The X argument is a pointer to a string which
 ** is the unexpanded SQL text of the prepared statement or an SQL comment 
 ** that indicates the invocation of a trigger.  ^The callback can compute
 ** the same text that would have been returned by the legacy [sqlite3_trace()]
 ** interface by using the X argument when X begins with "--" and invoking
 ** [sqlite3_expanded_sql(P)] otherwise.
 **
 ** [[SQLITE_TRACE_PROFILE]] <dt>SQLITE_TRACE_PROFILE</dt>
 ** <dd>^An SQLITE_TRACE_PROFILE callback provides approximately the same
 ** information as is provided by the [sqlite3_profile()] callback.
 ** ^The P argument is a pointer to the [prepared statement] and the
 ** X argument points to a 64-bit integer which is the estimated of
 ** the number of nanosecond that the prepared statement took to run.
 ** ^The SQLITE_TRACE_PROFILE callback is invoked when the statement finishes.
 **
 ** [[SQLITE_TRACE_ROW]] <dt>SQLITE_TRACE_ROW</dt>
 ** <dd>^An SQLITE_TRACE_ROW callback is invoked whenever a prepared
 ** statement generates a single row of result.  
 ** ^The P argument is a pointer to the [prepared statement] and the
 ** X argument is unused.
 **
 ** [[SQLITE_TRACE_CLOSE]] <dt>SQLITE_TRACE_CLOSE</dt>
 ** <dd>^An SQLITE_TRACE_CLOSE callback is invoked when a database
 ** connection closes.
 ** ^The P argument is a pointer to the [database connection] object
 ** and the X argument is unused.
 ** </dl>
 */
 #define SQLITE_TRACE_STMT       0x01
 #define SQLITE_TRACE_PROFILE    0x02
 #define SQLITE_TRACE_ROW        0x04
 #define SQLITE_TRACE_CLOSE      0x08
 
 /*
 ** CAPI3REF: SQL Trace Hook
 ** METHOD: sqlite3
 **
 ** ^The sqlite3_trace_v2(D,M,X,P) interface registers a trace callback
 ** function X against [database connection] D, using property mask M
 ** and context pointer P.  ^If the X callback is
 ** NULL or if the M mask is zero, then tracing is disabled.  The
 ** M argument should be the bitwise OR-ed combination of
 ** zero or more [SQLITE_TRACE] constants.
 **
 ** ^Each call to either sqlite3_trace() or sqlite3_trace_v2() overrides 
 ** (cancels) any prior calls to sqlite3_trace() or sqlite3_trace_v2().
 **
 ** ^The X callback is invoked whenever any of the events identified by 
 ** mask M occur.  ^The integer return value from the callback is currently
 ** ignored, though this may change in future releases.  Callback
 ** implementations should return zero to ensure future compatibility.
 **
 ** ^A trace callback is invoked with four arguments: callback(T,C,P,X).
 ** ^The T argument is one of the [SQLITE_TRACE]
 ** constants to indicate why the callback was invoked.
 ** ^The C argument is a copy of the context pointer.
 ** The P and X arguments are pointers whose meanings depend on T.
 **
 ** The sqlite3_trace_v2() interface is intended to replace the legacy
 ** interfaces [sqlite3_trace()] and [sqlite3_profile()], both of which
 ** are deprecated.
 */
 SQLITE_API int sqlite3_trace_v2(
   sqlite3*,
   unsigned uMask,
   int(*xCallback)(unsigned,void*,void*,void*),
   void *pCtx
 );
 
 /*
 ** CAPI3REF: Query Progress Callbacks
 ** METHOD: sqlite3
 **
 ** ^The sqlite3_progress_handler(D,N,X,P) interface causes the callback
 ** function X to be invoked periodically during long running calls to
 ** [sqlite3_exec()], [sqlite3_step()] and [sqlite3_get_table()] for
 ** database connection D.  An example use for this
 ** interface is to keep a GUI updated during a large query.
 **
 ** ^The parameter P is passed through as the only parameter to the 
 ** callback function X.  ^The parameter N is the approximate number of 
 ** [virtual machine instructions] that are evaluated between successive
 ** invocations of the callback X.  ^If N is less than one then the progress
 ** handler is disabled.
 **
 ** ^Only a single progress handler may be defined at one time per
 ** [database connection]; setting a new progress handler cancels the
 ** old one.  ^Setting parameter X to NULL disables the progress handler.
 ** ^The progress handler is also disabled by setting N to a value less
 ** than 1.
 **
 ** ^If the progress callback returns non-zero, the operation is
 ** interrupted.  This feature can be used to implement a
 ** "Cancel" button on a GUI progress dialog box.
 **
 ** The progress handler callback must not do anything that will modify
 ** the database connection that invoked the progress handler.
 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
 ** database connections for the meaning of "modify" in this paragraph.
 **
 */
 SQLITE_API void sqlite3_progress_handler(sqlite3*, int, int(*)(void*), void*);
 
 /*
 ** CAPI3REF: Opening A New Database Connection
 ** CONSTRUCTOR: sqlite3
 **
 ** ^These routines open an SQLite database file as specified by the 
 ** filename argument. ^The filename argument is interpreted as UTF-8 for
 ** sqlite3_open() and sqlite3_open_v2() and as UTF-16 in the native byte
 ** order for sqlite3_open16(). ^(A [database connection] handle is usually
 ** returned in *ppDb, even if an error occurs.  The only exception is that
 ** if SQLite is unable to allocate memory to hold the [sqlite3] object,
 ** a NULL will be written into *ppDb instead of a pointer to the [sqlite3]
 ** object.)^ ^(If the database is opened (and/or created) successfully, then
 ** [SQLITE_OK] is returned.  Otherwise an [error code] is returned.)^ ^The
 ** [sqlite3_errmsg()] or [sqlite3_errmsg16()] routines can be used to obtain
 ** an English language description of the error following a failure of any
 ** of the sqlite3_open() routines.
 **
 ** ^The default encoding will be UTF-8 for databases created using
 ** sqlite3_open() or sqlite3_open_v2().  ^The default encoding for databases
 ** created using sqlite3_open16() will be UTF-16 in the native byte order.
 **
 ** Whether or not an error occurs when it is opened, resources
 ** associated with the [database connection] handle should be released by
 ** passing it to [sqlite3_close()] when it is no longer required.
 **
 ** The sqlite3_open_v2() interface works like sqlite3_open()
 ** except that it accepts two additional parameters for additional control
 ** over the new database connection.  ^(The flags parameter to
 ** sqlite3_open_v2() can take one of
 ** the following three values, optionally combined with the 
 ** [SQLITE_OPEN_NOMUTEX], [SQLITE_OPEN_FULLMUTEX], [SQLITE_OPEN_SHAREDCACHE],
 ** [SQLITE_OPEN_PRIVATECACHE], and/or [SQLITE_OPEN_URI] flags:)^
 **
 ** <dl>
 ** ^(<dt>[SQLITE_OPEN_READONLY]</dt>
 ** <dd>The database is opened in read-only mode.  If the database does not
 ** already exist, an error is returned.</dd>)^
 **
 ** ^(<dt>[SQLITE_OPEN_READWRITE]</dt>
 ** <dd>The database is opened for reading and writing if possible, or reading
 ** only if the file is write protected by the operating system.  In either
 ** case the database must already exist, otherwise an error is returned.</dd>)^
 **
 ** ^(<dt>[SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]</dt>
 ** <dd>The database is opened for reading and writing, and is created if
 ** it does not already exist. This is the behavior that is always used for
 ** sqlite3_open() and sqlite3_open16().</dd>)^
 ** </dl>
 **
 ** If the 3rd parameter to sqlite3_open_v2() is not one of the
 ** combinations shown above optionally combined with other
 ** [SQLITE_OPEN_READONLY | SQLITE_OPEN_* bits]
 ** then the behavior is undefined.
 **
 ** ^If the [SQLITE_OPEN_NOMUTEX] flag is set, then the database connection
 ** opens in the multi-thread [threading mode] as long as the single-thread
 ** mode has not been set at compile-time or start-time.  ^If the
 ** [SQLITE_OPEN_FULLMUTEX] flag is set then the database connection opens
 ** in the serialized [threading mode] unless single-thread was
 ** previously selected at compile-time or start-time.
 ** ^The [SQLITE_OPEN_SHAREDCACHE] flag causes the database connection to be
 ** eligible to use [shared cache mode], regardless of whether or not shared
 ** cache is enabled using [sqlite3_enable_shared_cache()].  ^The
 ** [SQLITE_OPEN_PRIVATECACHE] flag causes the database connection to not
 ** participate in [shared cache mode] even if it is enabled.
 **
 ** ^The fourth parameter to sqlite3_open_v2() is the name of the
 ** [sqlite3_vfs] object that defines the operating system interface that
 ** the new database connection should use.  ^If the fourth parameter is
 ** a NULL pointer then the default [sqlite3_vfs] object is used.
 **
 ** ^If the filename is ":memory:", then a private, temporary in-memory database
 ** is created for the connection.  ^This in-memory database will vanish when
 ** the database connection is closed.  Future versions of SQLite might
 ** make use of additional special filenames that begin with the ":" character.
 ** It is recommended that when a database filename actually does begin with
 ** a ":" character you should prefix the filename with a pathname such as
 ** "./" to avoid ambiguity.
 **
 ** ^If the filename is an empty string, then a private, temporary
 ** on-disk database will be created.  ^This private database will be
 ** automatically deleted as soon as the database connection is closed.
 **
 ** [[URI filenames in sqlite3_open()]] <h3>URI Filenames</h3>
 **
 ** ^If [URI filename] interpretation is enabled, and the filename argument
 ** begins with "file:", then the filename is interpreted as a URI. ^URI
 ** filename interpretation is enabled if the [SQLITE_OPEN_URI] flag is
 ** set in the third argument to sqlite3_open_v2(), or if it has
 ** been enabled globally using the [SQLITE_CONFIG_URI] option with the
 ** [sqlite3_config()] method or by the [SQLITE_USE_URI] compile-time option.
 ** URI filename interpretation is turned off
 ** by default, but future releases of SQLite might enable URI filename
 ** interpretation by default.  See "[URI filenames]" for additional
 ** information.
 **
 ** URI filenames are parsed according to RFC 3986. ^If the URI contains an
 ** authority, then it must be either an empty string or the string 
 ** "localhost". ^If the authority is not an empty string or "localhost", an 
 ** error is returned to the caller. ^The fragment component of a URI, if 
 ** present, is ignored.
 **
 ** ^SQLite uses the path component of the URI as the name of the disk file
 ** which contains the database. ^If the path begins with a '/' character, 
 ** then it is interpreted as an absolute path. ^If the path does not begin 
 ** with a '/' (meaning that the authority section is omitted from the URI)
 ** then the path is interpreted as a relative path. 
 ** ^(On windows, the first component of an absolute path 
 ** is a drive specification (e.g. "C:").)^
 **
 ** [[core URI query parameters]]
 ** The query component of a URI may contain parameters that are interpreted
 ** either by SQLite itself, or by a [VFS | custom VFS implementation].
 ** SQLite and its built-in [VFSes] interpret the
 ** following query parameters:
 **
 ** <ul>
 **   <li> <b>vfs</b>: ^The "vfs" parameter may be used to specify the name of
 **     a VFS object that provides the operating system interface that should
 **     be used to access the database file on disk. ^If this option is set to
 **     an empty string the default VFS object is used. ^Specifying an unknown
 **     VFS is an error. ^If sqlite3_open_v2() is used and the vfs option is
 **     present, then the VFS specified by the option takes precedence over
 **     the value passed as the fourth parameter to sqlite3_open_v2().
 **
 **   <li> <b>mode</b>: ^(The mode parameter may be set to either "ro", "rw",
 **     "rwc", or "memory". Attempting to set it to any other value is
 **     an error)^. 
 **     ^If "ro" is specified, then the database is opened for read-only 
 **     access, just as if the [SQLITE_OPEN_READONLY] flag had been set in the 
 **     third argument to sqlite3_open_v2(). ^If the mode option is set to 
 **     "rw", then the database is opened for read-write (but not create) 
 **     access, as if SQLITE_OPEN_READWRITE (but not SQLITE_OPEN_CREATE) had 
 **     been set. ^Value "rwc" is equivalent to setting both 
 **     SQLITE_OPEN_READWRITE and SQLITE_OPEN_CREATE.  ^If the mode option is
 **     set to "memory" then a pure [in-memory database] that never reads
 **     or writes from disk is used. ^It is an error to specify a value for
 **     the mode parameter that is less restrictive than that specified by
 **     the flags passed in the third parameter to sqlite3_open_v2().
 **
 **   <li> <b>cache</b>: ^The cache parameter may be set to either "shared" or
 **     "private". ^Setting it to "shared" is equivalent to setting the
 **     SQLITE_OPEN_SHAREDCACHE bit in the flags argument passed to
 **     sqlite3_open_v2(). ^Setting the cache parameter to "private" is 
 **     equivalent to setting the SQLITE_OPEN_PRIVATECACHE bit.
 **     ^If sqlite3_open_v2() is used and the "cache" parameter is present in
 **     a URI filename, its value overrides any behavior requested by setting
 **     SQLITE_OPEN_PRIVATECACHE or SQLITE_OPEN_SHAREDCACHE flag.
 **
 **  <li> <b>psow</b>: ^The psow parameter indicates whether or not the
 **     [powersafe overwrite] property does or does not apply to the
 **     storage media on which the database file resides.
 **
 **  <li> <b>nolock</b>: ^The nolock parameter is a boolean query parameter
 **     which if set disables file locking in rollback journal modes.  This
 **     is useful for accessing a database on a filesystem that does not
 **     support locking.  Caution:  Database corruption might result if two
 **     or more processes write to the same database and any one of those
 **     processes uses nolock=1.
 **
 **  <li> <b>immutable</b>: ^The immutable parameter is a boolean query
 **     parameter that indicates that the database file is stored on
 **     read-only media.  ^When immutable is set, SQLite assumes that the
 **     database file cannot be changed, even by a process with higher
 **     privilege, and so the database is opened read-only and all locking
 **     and change detection is disabled.  Caution: Setting the immutable
 **     property on a database file that does in fact change can result
 **     in incorrect query results and/or [SQLITE_CORRUPT] errors.
 **     See also: [SQLITE_IOCAP_IMMUTABLE].
 **       
 ** </ul>
 **
 ** ^Specifying an unknown parameter in the query component of a URI is not an
 ** error.  Future versions of SQLite might understand additional query
 ** parameters.  See "[query parameters with special meaning to SQLite]" for
 ** additional information.
 **
 ** [[URI filename examples]] <h3>URI filename examples</h3>
 **
 ** <table border="1" align=center cellpadding=5>
 ** <tr><th> URI filenames <th> Results
 ** <tr><td> file:data.db <td> 
 **          Open the file "data.db" in the current directory.
 ** <tr><td> file:/home/fred/data.db<br>
 **          file:///home/fred/data.db <br> 
 **          file://localhost/home/fred/data.db <br> <td> 
 **          Open the database file "/home/fred/data.db".
 ** <tr><td> file://darkstar/home/fred/data.db <td> 
 **          An error. "darkstar" is not a recognized authority.
 ** <tr><td style="white-space:nowrap"> 
 **          file:///C:/Documents%20and%20Settings/fred/Desktop/data.db
 **     <td> Windows only: Open the file "data.db" on fred's desktop on drive
 **          C:. Note that the %20 escaping in this example is not strictly 
 **          necessary - space characters can be used literally
 **          in URI filenames.
 ** <tr><td> file:data.db?mode=ro&cache=private <td> 
 **          Open file "data.db" in the current directory for read-only access.
 **          Regardless of whether or not shared-cache mode is enabled by
 **          default, use a private cache.
 ** <tr><td> file:/home/fred/data.db?vfs=unix-dotfile <td>
 **          Open file "/home/fred/data.db". Use the special VFS "unix-dotfile"
 **          that uses dot-files in place of posix advisory locking.
 ** <tr><td> file:data.db?mode=readonly <td> 
 **          An error. "readonly" is not a valid option for the "mode" parameter.
 ** </table>
 **
 ** ^URI hexadecimal escape sequences (%HH) are supported within the path and
 ** query components of a URI. A hexadecimal escape sequence consists of a
 ** percent sign - "%" - followed by exactly two hexadecimal digits 
 ** specifying an octet value. ^Before the path or query components of a
 ** URI filename are interpreted, they are encoded using UTF-8 and all 
 ** hexadecimal escape sequences replaced by a single byte containing the
 ** corresponding octet. If this process generates an invalid UTF-8 encoding,
 ** the results are undefined.
 **
 ** <b>Note to Windows users:</b>  The encoding used for the filename argument
 ** of sqlite3_open() and sqlite3_open_v2() must be UTF-8, not whatever
 ** codepage is currently defined.  Filenames containing international
 ** characters must be converted to UTF-8 prior to passing them into
 ** sqlite3_open() or sqlite3_open_v2().
 **
 ** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
 ** prior to calling sqlite3_open() or sqlite3_open_v2().  Otherwise, various
 ** features that require the use of temporary files may fail.
 **
 ** See also: [sqlite3_temp_directory]
 */
 SQLITE_API int sqlite3_open(
   const char *filename,   /* Database filename (UTF-8) */
   sqlite3 **ppDb          /* OUT: SQLite db handle */
 );
 SQLITE_API int sqlite3_open16(
   const void *filename,   /* Database filename (UTF-16) */
   sqlite3 **ppDb          /* OUT: SQLite db handle */
 );
 SQLITE_API int sqlite3_open_v2(
   const char *filename,   /* Database filename (UTF-8) */
   sqlite3 **ppDb,         /* OUT: SQLite db handle */
   int flags,              /* Flags */
   const char *zVfs        /* Name of VFS module to use */
 );
 
 /*
 ** CAPI3REF: Obtain Values For URI Parameters
 **
 ** These are utility routines, useful to VFS implementations, that check
 ** to see if a database file was a URI that contained a specific query 
 ** parameter, and if so obtains the value of that query parameter.
 **
 ** If F is the database filename pointer passed into the xOpen() method of 
 ** a VFS implementation when the flags parameter to xOpen() has one or 
 ** more of the [SQLITE_OPEN_URI] or [SQLITE_OPEN_MAIN_DB] bits set and
 ** P is the name of the query parameter, then
 ** sqlite3_uri_parameter(F,P) returns the value of the P
 ** parameter if it exists or a NULL pointer if P does not appear as a 
 ** query parameter on F.  If P is a query parameter of F
 ** has no explicit value, then sqlite3_uri_parameter(F,P) returns
 ** a pointer to an empty string.
 **
 ** The sqlite3_uri_boolean(F,P,B) routine assumes that P is a boolean
 ** parameter and returns true (1) or false (0) according to the value
 ** of P.  The sqlite3_uri_boolean(F,P,B) routine returns true (1) if the
 ** value of query parameter P is one of "yes", "true", or "on" in any
 ** case or if the value begins with a non-zero number.  The 
 ** sqlite3_uri_boolean(F,P,B) routines returns false (0) if the value of
 ** query parameter P is one of "no", "false", or "off" in any case or
 ** if the value begins with a numeric zero.  If P is not a query
 ** parameter on F or if the value of P is does not match any of the
 ** above, then sqlite3_uri_boolean(F,P,B) returns (B!=0).
 **
 ** The sqlite3_uri_int64(F,P,D) routine converts the value of P into a
 ** 64-bit signed integer and returns that integer, or D if P does not
 ** exist.  If the value of P is something other than an integer, then
 ** zero is returned.
 ** 
 ** If F is a NULL pointer, then sqlite3_uri_parameter(F,P) returns NULL and
 ** sqlite3_uri_boolean(F,P,B) returns B.  If F is not a NULL pointer and
 ** is not a database file pathname pointer that SQLite passed into the xOpen
 ** VFS method, then the behavior of this routine is undefined and probably
 ** undesirable.
 */
 SQLITE_API const char *sqlite3_uri_parameter(const char *zFilename, const char *zParam);
 SQLITE_API int sqlite3_uri_boolean(const char *zFile, const char *zParam, int bDefault);
 SQLITE_API sqlite3_int64 sqlite3_uri_int64(const char*, const char*, sqlite3_int64);
 
 
 /*
 ** CAPI3REF: Error Codes And Messages
 ** METHOD: sqlite3
 **
 ** ^If the most recent sqlite3_* API call associated with 
 ** [database connection] D failed, then the sqlite3_errcode(D) interface
 ** returns the numeric [result code] or [extended result code] for that
 ** API call.
 ** If the most recent API call was successful,
 ** then the return value from sqlite3_errcode() is undefined.
 ** ^The sqlite3_extended_errcode()
 ** interface is the same except that it always returns the 
 ** [extended result code] even when extended result codes are
 ** disabled.
 **
 ** ^The sqlite3_errmsg() and sqlite3_errmsg16() return English-language
 ** text that describes the error, as either UTF-8 or UTF-16 respectively.
 ** ^(Memory to hold the error message string is managed internally.
 ** The application does not need to worry about freeing the result.
 ** However, the error string might be overwritten or deallocated by
 ** subsequent calls to other SQLite interface functions.)^
 **
 ** ^The sqlite3_errstr() interface returns the English-language text
 ** that describes the [result code], as UTF-8.
 ** ^(Memory to hold the error message string is managed internally
 ** and must not be freed by the application)^.
 **
 ** When the serialized [threading mode] is in use, it might be the
 ** case that a second error occurs on a separate thread in between
 ** the time of the first error and the call to these interfaces.
 ** When that happens, the second error will be reported since these
 ** interfaces always report the most recent result.  To avoid
 ** this, each thread can obtain exclusive use of the [database connection] D
 ** by invoking [sqlite3_mutex_enter]([sqlite3_db_mutex](D)) before beginning
 ** to use D and invoking [sqlite3_mutex_leave]([sqlite3_db_mutex](D)) after
 ** all calls to the interfaces listed here are completed.
 **
 ** If an interface fails with SQLITE_MISUSE, that means the interface
 ** was invoked incorrectly by the application.  In that case, the
 ** error code and message may or may not be set.
 */
 SQLITE_API int sqlite3_errcode(sqlite3 *db);
 SQLITE_API int sqlite3_extended_errcode(sqlite3 *db);
 SQLITE_API const char *sqlite3_errmsg(sqlite3*);
 SQLITE_API const void *sqlite3_errmsg16(sqlite3*);
 SQLITE_API const char *sqlite3_errstr(int);
 
 /*
 ** CAPI3REF: Prepared Statement Object
 ** KEYWORDS: {prepared statement} {prepared statements}
 **
 ** An instance of this object represents a single SQL statement that
 ** has been compiled into binary form and is ready to be evaluated.
 **
 ** Think of each SQL statement as a separate computer program.  The
 ** original SQL text is source code.  A prepared statement object 
 ** is the compiled object code.  All SQL must be converted into a
 ** prepared statement before it can be run.
 **
 ** The life-cycle of a prepared statement object usually goes like this:
 **
 ** <ol>
 ** <li> Create the prepared statement object using [sqlite3_prepare_v2()].
 ** <li> Bind values to [parameters] using the sqlite3_bind_*()
 **      interfaces.
 ** <li> Run the SQL by calling [sqlite3_step()] one or more times.
 ** <li> Reset the prepared statement using [sqlite3_reset()] then go back
 **      to step 2.  Do this zero or more times.
 ** <li> Destroy the object using [sqlite3_finalize()].
 ** </ol>
 */
 typedef struct sqlite3_stmt sqlite3_stmt;
 
 /*
 ** CAPI3REF: Run-time Limits
 ** METHOD: sqlite3
 **
 ** ^(This interface allows the size of various constructs to be limited
 ** on a connection by connection basis.  The first parameter is the
 ** [database connection] whose limit is to be set or queried.  The
 ** second parameter is one of the [limit categories] that define a
 ** class of constructs to be size limited.  The third parameter is the
 ** new limit for that construct.)^
 **
 ** ^If the new limit is a negative number, the limit is unchanged.
 ** ^(For each limit category SQLITE_LIMIT_<i>NAME</i> there is a 
 ** [limits | hard upper bound]
 ** set at compile-time by a C preprocessor macro called
 ** [limits | SQLITE_MAX_<i>NAME</i>].
 ** (The "_LIMIT_" in the name is changed to "_MAX_".))^
 ** ^Attempts to increase a limit above its hard upper bound are
 ** silently truncated to the hard upper bound.
 **
 ** ^Regardless of whether or not the limit was changed, the 
 ** [sqlite3_limit()] interface returns the prior value of the limit.
 ** ^Hence, to find the current value of a limit without changing it,
 ** simply invoke this interface with the third parameter set to -1.
 **
 ** Run-time limits are intended for use in applications that manage
 ** both their own internal database and also databases that are controlled
 ** by untrusted external sources.  An example application might be a
 ** web browser that has its own databases for storing history and
 ** separate databases controlled by JavaScript applications downloaded
 ** off the Internet.  The internal databases can be given the
 ** large, default limits.  Databases managed by external sources can
 ** be given much smaller limits designed to prevent a denial of service
 ** attack.  Developers might also want to use the [sqlite3_set_authorizer()]
 ** interface to further control untrusted SQL.  The size of the database
 ** created by an untrusted script can be contained using the
 ** [max_page_count] [PRAGMA].
 **
 ** New run-time limit categories may be added in future releases.
 */
 SQLITE_API int sqlite3_limit(sqlite3*, int id, int newVal);
 
 /*
 ** CAPI3REF: Run-Time Limit Categories
 ** KEYWORDS: {limit category} {*limit categories}
 **
 ** These constants define various performance limits
 ** that can be lowered at run-time using [sqlite3_limit()].
 ** The synopsis of the meanings of the various limits is shown below.
 ** Additional information is available at [limits | Limits in SQLite].
 **
 ** <dl>
 ** [[SQLITE_LIMIT_LENGTH]] ^(<dt>SQLITE_LIMIT_LENGTH</dt>
 ** <dd>The maximum size of any string or BLOB or table row, in bytes.<dd>)^
 **
 ** [[SQLITE_LIMIT_SQL_LENGTH]] ^(<dt>SQLITE_LIMIT_SQL_LENGTH</dt>
 ** <dd>The maximum length of an SQL statement, in bytes.</dd>)^
 **
 ** [[SQLITE_LIMIT_COLUMN]] ^(<dt>SQLITE_LIMIT_COLUMN</dt>
 ** <dd>The maximum number of columns in a table definition or in the
 ** result set of a [SELECT] or the maximum number of columns in an index
 ** or in an ORDER BY or GROUP BY clause.</dd>)^
 **
 ** [[SQLITE_LIMIT_EXPR_DEPTH]] ^(<dt>SQLITE_LIMIT_EXPR_DEPTH</dt>
 ** <dd>The maximum depth of the parse tree on any expression.</dd>)^
 **
 ** [[SQLITE_LIMIT_COMPOUND_SELECT]] ^(<dt>SQLITE_LIMIT_COMPOUND_SELECT</dt>
 ** <dd>The maximum number of terms in a compound SELECT statement.</dd>)^
 **
 ** [[SQLITE_LIMIT_VDBE_OP]] ^(<dt>SQLITE_LIMIT_VDBE_OP</dt>
 ** <dd>The maximum number of instructions in a virtual machine program
 ** used to implement an SQL statement.  If [sqlite3_prepare_v2()] or
 ** the equivalent tries to allocate space for more than this many opcodes
 ** in a single prepared statement, an SQLITE_NOMEM error is returned.</dd>)^
 **
 ** [[SQLITE_LIMIT_FUNCTION_ARG]] ^(<dt>SQLITE_LIMIT_FUNCTION_ARG</dt>
 ** <dd>The maximum number of arguments on a function.</dd>)^
 **
 ** [[SQLITE_LIMIT_ATTACHED]] ^(<dt>SQLITE_LIMIT_ATTACHED</dt>
 ** <dd>The maximum number of [ATTACH | attached databases].)^</dd>
 **
 ** [[SQLITE_LIMIT_LIKE_PATTERN_LENGTH]]
 ** ^(<dt>SQLITE_LIMIT_LIKE_PATTERN_LENGTH</dt>
 ** <dd>The maximum length of the pattern argument to the [LIKE] or
 ** [GLOB] operators.</dd>)^
 **
 ** [[SQLITE_LIMIT_VARIABLE_NUMBER]]
 ** ^(<dt>SQLITE_LIMIT_VARIABLE_NUMBER</dt>
 ** <dd>The maximum index number of any [parameter] in an SQL statement.)^
 **
 ** [[SQLITE_LIMIT_TRIGGER_DEPTH]] ^(<dt>SQLITE_LIMIT_TRIGGER_DEPTH</dt>
 ** <dd>The maximum depth of recursion for triggers.</dd>)^
 **
 ** [[SQLITE_LIMIT_WORKER_THREADS]] ^(<dt>SQLITE_LIMIT_WORKER_THREADS</dt>
 ** <dd>The maximum number of auxiliary worker threads that a single
 ** [prepared statement] may start.</dd>)^
 ** </dl>
 */
 #define SQLITE_LIMIT_LENGTH                    0
 #define SQLITE_LIMIT_SQL_LENGTH                1
 #define SQLITE_LIMIT_COLUMN                    2
 #define SQLITE_LIMIT_EXPR_DEPTH                3
 #define SQLITE_LIMIT_COMPOUND_SELECT           4
 #define SQLITE_LIMIT_VDBE_OP                   5
 #define SQLITE_LIMIT_FUNCTION_ARG              6
 #define SQLITE_LIMIT_ATTACHED                  7
 #define SQLITE_LIMIT_LIKE_PATTERN_LENGTH       8
 #define SQLITE_LIMIT_VARIABLE_NUMBER           9
 #define SQLITE_LIMIT_TRIGGER_DEPTH            10
 #define SQLITE_LIMIT_WORKER_THREADS           11
 
 /*
 ** CAPI3REF: Prepare Flags
 **
 ** These constants define various flags that can be passed into
 ** "prepFlags" parameter of the [sqlite3_prepare_v3()] and
 ** [sqlite3_prepare16_v3()] interfaces.
 **
 ** New flags may be added in future releases of SQLite.
 **
 ** <dl>
 ** [[SQLITE_PREPARE_PERSISTENT]] ^(<dt>SQLITE_PREPARE_PERSISTENT</dt>
 ** <dd>The SQLITE_PREPARE_PERSISTENT flag is a hint to the query planner
 ** that the prepared statement will be retained for a long time and
 ** probably reused many times.)^ ^Without this flag, [sqlite3_prepare_v3()]
 ** and [sqlite3_prepare16_v3()] assume that the prepared statement will 
 ** be used just once or at most a few times and then destroyed using
 ** [sqlite3_finalize()] relatively soon. The current implementation acts
 ** on this hint by avoiding the use of [lookaside memory] so as not to
 ** deplete the limited store of lookaside memory. Future versions of
 ** SQLite may act on this hint differently.
 ** </dl>
 */
 #define SQLITE_PREPARE_PERSISTENT              0x01
 
 /*
 ** CAPI3REF: Compiling An SQL Statement
 ** KEYWORDS: {SQL statement compiler}
 ** METHOD: sqlite3
 ** CONSTRUCTOR: sqlite3_stmt
 **
 ** To execute an SQL statement, it must first be compiled into a byte-code
 ** program using one of these routines.  Or, in other words, these routines
 ** are constructors for the [prepared statement] object.
 **
 ** The preferred routine to use is [sqlite3_prepare_v2()].  The
 ** [sqlite3_prepare()] interface is legacy and should be avoided.
 ** [sqlite3_prepare_v3()] has an extra "prepFlags" option that is used
 ** for special purposes.
 **
 ** The use of the UTF-8 interfaces is preferred, as SQLite currently
 ** does all parsing using UTF-8.  The UTF-16 interfaces are provided
 ** as a convenience.  The UTF-16 interfaces work by converting the
 ** input text into UTF-8, then invoking the corresponding UTF-8 interface.
 **
 ** The first argument, "db", is a [database connection] obtained from a
 ** prior successful call to [sqlite3_open()], [sqlite3_open_v2()] or
 ** [sqlite3_open16()].  The database connection must not have been closed.
 **
 ** The second argument, "zSql", is the statement to be compiled, encoded
 ** as either UTF-8 or UTF-16.  The sqlite3_prepare(), sqlite3_prepare_v2(),
 ** and sqlite3_prepare_v3()
 ** interfaces use UTF-8, and sqlite3_prepare16(), sqlite3_prepare16_v2(),
 ** and sqlite3_prepare16_v3() use UTF-16.
 **
 ** ^If the nByte argument is negative, then zSql is read up to the
 ** first zero terminator. ^If nByte is positive, then it is the
 ** number of bytes read from zSql.  ^If nByte is zero, then no prepared
 ** statement is generated.
 ** If the caller knows that the supplied string is nul-terminated, then
 ** there is a small performance advantage to passing an nByte parameter that
 ** is the number of bytes in the input string <i>including</i>
 ** the nul-terminator.
 **
 ** ^If pzTail is not NULL then *pzTail is made to point to the first byte
 ** past the end of the first SQL statement in zSql.  These routines only
 ** compile the first statement in zSql, so *pzTail is left pointing to
 ** what remains uncompiled.
 **
 ** ^*ppStmt is left pointing to a compiled [prepared statement] that can be
 ** executed using [sqlite3_step()].  ^If there is an error, *ppStmt is set
 ** to NULL.  ^If the input text contains no SQL (if the input is an empty
 ** string or a comment) then *ppStmt is set to NULL.
 ** The calling procedure is responsible for deleting the compiled
 ** SQL statement using [sqlite3_finalize()] after it has finished with it.
 ** ppStmt may not be NULL.
 **
 ** ^On success, the sqlite3_prepare() family of routines return [SQLITE_OK];
 ** otherwise an [error code] is returned.
 **
 ** The sqlite3_prepare_v2(), sqlite3_prepare_v3(), sqlite3_prepare16_v2(),
 ** and sqlite3_prepare16_v3() interfaces are recommended for all new programs.
 ** The older interfaces (sqlite3_prepare() and sqlite3_prepare16())
 ** are retained for backwards compatibility, but their use is discouraged.
 ** ^In the "vX" interfaces, the prepared statement
 ** that is returned (the [sqlite3_stmt] object) contains a copy of the
 ** original SQL text. This causes the [sqlite3_step()] interface to
 ** behave differently in three ways:
 **
 ** <ol>
 ** <li>
 ** ^If the database schema changes, instead of returning [SQLITE_SCHEMA] as it
 ** always used to do, [sqlite3_step()] will automatically recompile the SQL
 ** statement and try to run it again. As many as [SQLITE_MAX_SCHEMA_RETRY]
 ** retries will occur before sqlite3_step() gives up and returns an error.
 ** </li>
 **
 ** <li>
 ** ^When an error occurs, [sqlite3_step()] will return one of the detailed
 ** [error codes] or [extended error codes].  ^The legacy behavior was that
 ** [sqlite3_step()] would only return a generic [SQLITE_ERROR] result code
 ** and the application would have to make a second call to [sqlite3_reset()]
 ** in order to find the underlying cause of the problem. With the "v2" prepare
 ** interfaces, the underlying reason for the error is returned immediately.
 ** </li>
 **
 ** <li>
 ** ^If the specific value bound to [parameter | host parameter] in the 
 ** WHERE clause might influence the choice of query plan for a statement,
 ** then the statement will be automatically recompiled, as if there had been 
 ** a schema change, on the first  [sqlite3_step()] call following any change
 ** to the [sqlite3_bind_text | bindings] of that [parameter]. 
 ** ^The specific value of WHERE-clause [parameter] might influence the 
 ** choice of query plan if the parameter is the left-hand side of a [LIKE]
 ** or [GLOB] operator or if the parameter is compared to an indexed column
 ** and the [SQLITE_ENABLE_STAT3] compile-time option is enabled.
 ** </li>
 **
 ** <p>^sqlite3_prepare_v3() differs from sqlite3_prepare_v2() only in having
 ** the extra prepFlags parameter, which is a bit array consisting of zero or
 ** more of the [SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_*] flags.  ^The
 ** sqlite3_prepare_v2() interface works exactly the same as
 ** sqlite3_prepare_v3() with a zero prepFlags parameter.
 ** </ol>
 */
 SQLITE_API int sqlite3_prepare(
   sqlite3 *db,            /* Database handle */
   const char *zSql,       /* SQL statement, UTF-8 encoded */
   int nByte,              /* Maximum length of zSql in bytes. */
   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
 );
 SQLITE_API int sqlite3_prepare_v2(
   sqlite3 *db,            /* Database handle */
   const char *zSql,       /* SQL statement, UTF-8 encoded */
   int nByte,              /* Maximum length of zSql in bytes. */
   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
 );
 SQLITE_API int sqlite3_prepare_v3(
   sqlite3 *db,            /* Database handle */
   const char *zSql,       /* SQL statement, UTF-8 encoded */
   int nByte,              /* Maximum length of zSql in bytes. */
   unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
   const char **pzTail     /* OUT: Pointer to unused portion of zSql */
 );
 SQLITE_API int sqlite3_prepare16(
   sqlite3 *db,            /* Database handle */
   const void *zSql,       /* SQL statement, UTF-16 encoded */
   int nByte,              /* Maximum length of zSql in bytes. */
   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
 );
 SQLITE_API int sqlite3_prepare16_v2(
   sqlite3 *db,            /* Database handle */
   const void *zSql,       /* SQL statement, UTF-16 encoded */
   int nByte,              /* Maximum length of zSql in bytes. */
   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
 );
 SQLITE_API int sqlite3_prepare16_v3(
   sqlite3 *db,            /* Database handle */
   const void *zSql,       /* SQL statement, UTF-16 encoded */
   int nByte,              /* Maximum length of zSql in bytes. */
   unsigned int prepFlags, /* Zero or more SQLITE_PREPARE_ flags */
   sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
   const void **pzTail     /* OUT: Pointer to unused portion of zSql */
 );
 
 /*
 ** CAPI3REF: Retrieving Statement SQL
 ** METHOD: sqlite3_stmt
 **
 ** ^The sqlite3_sql(P) interface returns a pointer to a copy of the UTF-8
 ** SQL text used to create [prepared statement] P if P was
 ** created by [sqlite3_prepare_v2()], [sqlite3_prepare_v3()],
 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
 ** ^The sqlite3_expanded_sql(P) interface returns a pointer to a UTF-8
 ** string containing the SQL text of prepared statement P with
 ** [bound parameters] expanded.
 **
 ** ^(For example, if a prepared statement is created using the SQL
 ** text "SELECT $abc,:xyz" and if parameter $abc is bound to integer 2345
 ** and parameter :xyz is unbound, then sqlite3_sql() will return
 ** the original string, "SELECT $abc,:xyz" but sqlite3_expanded_sql()
 ** will return "SELECT 2345,NULL".)^
 **
 ** ^The sqlite3_expanded_sql() interface returns NULL if insufficient memory
 ** is available to hold the result, or if the result would exceed the
 ** the maximum string length determined by the [SQLITE_LIMIT_LENGTH].
 **
 ** ^The [SQLITE_TRACE_SIZE_LIMIT] compile-time option limits the size of
 ** bound parameter expansions.  ^The [SQLITE_OMIT_TRACE] compile-time
 ** option causes sqlite3_expanded_sql() to always return NULL.
 **
 ** ^The string returned by sqlite3_sql(P) is managed by SQLite and is
 ** automatically freed when the prepared statement is finalized.
 ** ^The string returned by sqlite3_expanded_sql(P), on the other hand,
 ** is obtained from [sqlite3_malloc()] and must be free by the application
 ** by passing it to [sqlite3_free()].
 */
 SQLITE_API const char *sqlite3_sql(sqlite3_stmt *pStmt);
 SQLITE_API char *sqlite3_expanded_sql(sqlite3_stmt *pStmt);
 
 /*
 ** CAPI3REF: Determine If An SQL Statement Writes The Database
 ** METHOD: sqlite3_stmt
 **
 ** ^The sqlite3_stmt_readonly(X) interface returns true (non-zero) if
 ** and only if the [prepared statement] X makes no direct changes to
 ** the content of the database file.
 **
 ** Note that [application-defined SQL functions] or
 ** [virtual tables] might change the database indirectly as a side effect.  
 ** ^(For example, if an application defines a function "eval()" that 
 ** calls [sqlite3_exec()], then the following SQL statement would
 ** change the database file through side-effects:
 **
 ** <blockquote><pre>
 **    SELECT eval('DELETE FROM t1') FROM t2;
 ** </pre></blockquote>
 **
 ** But because the [SELECT] statement does not change the database file
 ** directly, sqlite3_stmt_readonly() would still return true.)^
 **
 ** ^Transaction control statements such as [BEGIN], [COMMIT], [ROLLBACK],
 ** [SAVEPOINT], and [RELEASE] cause sqlite3_stmt_readonly() to return true,
 ** since the statements themselves do not actually modify the database but
 ** rather they control the timing of when other statements modify the 
 ** database.  ^The [ATTACH] and [DETACH] statements also cause
 ** sqlite3_stmt_readonly() to return true since, while those statements
 ** change the configuration of a database connection, they do not make 
 ** changes to the content of the database files on disk.
 ** ^The sqlite3_stmt_readonly() interface returns true for [BEGIN] since
 ** [BEGIN] merely sets internal flags, but the [BEGIN|BEGIN IMMEDIATE] and
 ** [BEGIN|BEGIN EXCLUSIVE] commands do touch the database and so
 ** sqlite3_stmt_readonly() returns false for those commands.
 */
 SQLITE_API int sqlite3_stmt_readonly(sqlite3_stmt *pStmt);
 
 /*
 ** CAPI3REF: Determine If A Prepared Statement Has Been Reset
 ** METHOD: sqlite3_stmt
 **
 ** ^The sqlite3_stmt_busy(S) interface returns true (non-zero) if the
 ** [prepared statement] S has been stepped at least once using 
 ** [sqlite3_step(S)] but has neither run to completion (returned
 ** [SQLITE_DONE] from [sqlite3_step(S)]) nor
 ** been reset using [sqlite3_reset(S)].  ^The sqlite3_stmt_busy(S)
 ** interface returns false if S is a NULL pointer.  If S is not a 
 ** NULL pointer and is not a pointer to a valid [prepared statement]
 ** object, then the behavior is undefined and probably undesirable.
 **
 ** This interface can be used in combination [sqlite3_next_stmt()]
 ** to locate all prepared statements associated with a database 
 ** connection that are in need of being reset.  This can be used,
 ** for example, in diagnostic routines to search for prepared 
 ** statements that are holding a transaction open.
 */
 SQLITE_API int sqlite3_stmt_busy(sqlite3_stmt*);
 
 /*
 ** CAPI3REF: Dynamically Typed Value Object
 ** KEYWORDS: {protected sqlite3_value} {unprotected sqlite3_value}
 **
 ** SQLite uses the sqlite3_value object to represent all values
 ** that can be stored in a database table. SQLite uses dynamic typing
 ** for the values it stores.  ^Values stored in sqlite3_value objects
 ** can be integers, floating point values, strings, BLOBs, or NULL.
 **
 ** An sqlite3_value object may be either "protected" or "unprotected".
 ** Some interfaces require a protected sqlite3_value.  Other interfaces
 ** will accept either a protected or an unprotected sqlite3_value.
 ** Every interface that accepts sqlite3_value arguments specifies
 ** whether or not it requires a protected sqlite3_value.  The
 ** [sqlite3_value_dup()] interface can be used to construct a new 
 ** protected sqlite3_value from an unprotected sqlite3_value.
 **
 ** The terms "protected" and "unprotected" refer to whether or not
 ** a mutex is held.  An internal mutex is held for a protected
 ** sqlite3_value object but no mutex is held for an unprotected
 ** sqlite3_value object.  If SQLite is compiled to be single-threaded
 ** (with [SQLITE_THREADSAFE=0] and with [sqlite3_threadsafe()] returning 0)
 ** or if SQLite is run in one of reduced mutex modes 
 ** [SQLITE_CONFIG_SINGLETHREAD] or [SQLITE_CONFIG_MULTITHREAD]
 ** then there is no distinction between protected and unprotected
 ** sqlite3_value objects and they can be used interchangeably.  However,
 ** for maximum code portability it is recommended that applications
 ** still make the distinction between protected and unprotected
 ** sqlite3_value objects even when not strictly required.
 **
 ** ^The sqlite3_value objects that are passed as parameters into the
 ** implementation of [application-defined SQL functions] are protected.
 ** ^The sqlite3_value object returned by
 ** [sqlite3_column_value()] is unprotected.
 ** Unprotected sqlite3_value objects may only be used as arguments
 ** to [sqlite3_result_value()], [sqlite3_bind_value()], and
 ** [sqlite3_value_dup()].
 ** The [sqlite3_value_blob | sqlite3_value_type()] family of
 ** interfaces require protected sqlite3_value objects.
 */
 typedef struct sqlite3_value sqlite3_value;
 
 /*
 ** CAPI3REF: SQL Function Context Object
 **
 ** The context in which an SQL function executes is stored in an
 ** sqlite3_context object.  ^A pointer to an sqlite3_context object
 ** is always first parameter to [application-defined SQL functions].
 ** The application-defined SQL function implementation will pass this
 ** pointer through into calls to [sqlite3_result_int | sqlite3_result()],
 ** [sqlite3_aggregate_context()], [sqlite3_user_data()],
 ** [sqlite3_context_db_handle()], [sqlite3_get_auxdata()],
 ** and/or [sqlite3_set_auxdata()].
 */
 typedef struct sqlite3_context sqlite3_context;
 
 /*
 ** CAPI3REF: Binding Values To Prepared Statements
 ** KEYWORDS: {host parameter} {host parameters} {host parameter name}
 ** KEYWORDS: {SQL parameter} {SQL parameters} {parameter binding}
 ** METHOD: sqlite3_stmt
 **
 ** ^(In the SQL statement text input to [sqlite3_prepare_v2()] and its variants,
 ** literals may be replaced by a [parameter] that matches one of following
 ** templates:
 **
 ** <ul>
 ** <li>  ?
 ** <li>  ?NNN
 ** <li>  :VVV
 ** <li>  @VVV
 ** <li>  $VVV
 ** </ul>
 **
 ** In the templates above, NNN represents an integer literal,
 ** and VVV represents an alphanumeric identifier.)^  ^The values of these
 ** parameters (also called "host parameter names" or "SQL parameters")
 ** can be set using the sqlite3_bind_*() routines defined here.
 **
 ** ^The first argument to the sqlite3_bind_*() routines is always
 ** a pointer to the [sqlite3_stmt] object returned from
 ** [sqlite3_prepare_v2()] or its variants.
 **
 ** ^The second argument is the index of the SQL parameter to be set.
 ** ^The leftmost SQL parameter has an index of 1.  ^When the same named
 ** SQL parameter is used more than once, second and subsequent
 ** occurrences have the same index as the first occurrence.
 ** ^The index for named parameters can be looked up using the
 ** [sqlite3_bind_parameter_index()] API if desired.  ^The index
 ** for "?NNN" parameters is the value of NNN.
 ** ^The NNN value must be between 1 and the [sqlite3_limit()]
 ** parameter [SQLITE_LIMIT_VARIABLE_NUMBER] (default value: 999).
 **
 ** ^The third argument is the value to bind to the parameter.
 ** ^If the third parameter to sqlite3_bind_text() or sqlite3_bind_text16()
 ** or sqlite3_bind_blob() is a NULL pointer then the fourth parameter
 ** is ignored and the end result is the same as sqlite3_bind_null().
 **
 ** ^(In those routines that have a fourth argument, its value is the
 ** number of bytes in the parameter.  To be clear: the value is the
 ** number of <u>bytes</u> in the value, not the number of characters.)^
 ** ^If the fourth parameter to sqlite3_bind_text() or sqlite3_bind_text16()
 ** is negative, then the length of the string is
 ** the number of bytes up to the first zero terminator.
 ** If the fourth parameter to sqlite3_bind_blob() is negative, then
 ** the behavior is undefined.
 ** If a non-negative fourth parameter is provided to sqlite3_bind_text()
 ** or sqlite3_bind_text16() or sqlite3_bind_text64() then
 ** that parameter must be the byte offset
 ** where the NUL terminator would occur assuming the string were NUL
 ** terminated.  If any NUL characters occur at byte offsets less than 
 ** the value of the fourth parameter then the resulting string value will
 ** contain embedded NULs.  The result of expressions involving strings
 ** with embedded NULs is undefined.
 **
 ** ^The fifth argument to the BLOB and string binding interfaces
 ** is a destructor used to dispose of the BLOB or
 ** string after SQLite has finished with it.  ^The destructor is called
 ** to dispose of the BLOB or string even if the call to bind API fails.
 ** ^If the fifth argument is
 ** the special value [SQLITE_STATIC], then SQLite assumes that the
 ** information is in static, unmanaged space and does not need to be freed.
 ** ^If the fifth argument has the value [SQLITE_TRANSIENT], then
 ** SQLite makes its own private copy of the data immediately, before
 ** the sqlite3_bind_*() routine returns.
 **
 ** ^The sixth argument to sqlite3_bind_text64() must be one of
 ** [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE]
 ** to specify the encoding of the text in the third parameter.  If
 ** the sixth argument to sqlite3_bind_text64() is not one of the
 ** allowed values shown above, or if the text encoding is different
 ** from the encoding specified by the sixth parameter, then the behavior
 ** is undefined.
 **
 ** ^The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
 ** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
 ** (just an integer to hold its size) while it is being processed.
 ** Zeroblobs are intended to serve as placeholders for BLOBs whose
 ** content is later written using
 ** [sqlite3_blob_open | incremental BLOB I/O] routines.
 ** ^A negative value for the zeroblob results in a zero-length BLOB.
 **
 ** ^The sqlite3_bind_pointer(S,I,P,T,D) routine causes the I-th parameter in
 ** [prepared statement] S to have an SQL value of NULL, but to also be
 ** associated with the pointer P of type T.  ^D is either a NULL pointer or
 ** a pointer to a destructor function for P. ^SQLite will invoke the
 ** destructor D with a single argument of P when it is finished using
 ** P.  The T parameter should be a static string, preferably a string
 ** literal. The sqlite3_bind_pointer() routine is part of the
 ** [pointer passing interface] added for SQLite 3.20.0.
 **
 ** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer
 ** for the [prepared statement] or with a prepared statement for which
 ** [sqlite3_step()] has been called more recently than [sqlite3_reset()],
 ** then the call will return [SQLITE_MISUSE].  If any sqlite3_bind_()
 ** routine is passed a [prepared statement] that has been finalized, the
 ** result is undefined and probably harmful.
 **
 ** ^Bindings are not cleared by the [sqlite3_reset()] routine.
 ** ^Unbound parameters are interpreted as NULL.
 **
 ** ^The sqlite3_bind_* routines return [SQLITE_OK] on success or an
 ** [error code] if anything goes wrong.
 ** ^[SQLITE_TOOBIG] might be returned if the size of a string or BLOB
 ** exceeds limits imposed by [sqlite3_limit]([SQLITE_LIMIT_LENGTH]) or
 ** [SQLITE_MAX_LENGTH].
 ** ^[SQLITE_RANGE] is returned if the parameter
 ** index is out of range.  ^[SQLITE_NOMEM] is returned if malloc() fails.
 **
 ** See also: [sqlite3_bind_parameter_count()],
 ** [sqlite3_bind_parameter_name()], and [sqlite3_bind_parameter_index()].
 */
 SQLITE_API int sqlite3_bind_blob(sqlite3_stmt*, int, const void*, int n, void(*)(void*));
 SQLITE_API int sqlite3_bind_blob64(sqlite3_stmt*, int, const void*, sqlite3_uint64,
                         void(*)(void*));
 SQLITE_API int sqlite3_bind_double(sqlite3_stmt*, int, double);
 SQLITE_API int sqlite3_bind_int(sqlite3_stmt*, int, int);
 SQLITE_API int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
 SQLITE_API int sqlite3_bind_null(sqlite3_stmt*, int);
 SQLITE_API int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
 SQLITE_API int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
 SQLITE_API int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
                          void(*)(void*), unsigned char encoding);
 SQLITE_API int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
 SQLITE_API int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*,void(*)(void*));
 SQLITE_API int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
 SQLITE_API int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);
 
 /*
 ** CAPI3REF: Number Of SQL Parameters
 ** METHOD: sqlite3_stmt
 **
 ** ^This routine can be used to find the number of [SQL parameters]
 ** in a [prepared statement].  SQL parameters are tokens of the
 ** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
 ** placeholders for values that are [sqlite3_bind_blob | bound]
 ** to the parameters at a later time.
 **
 ** ^(This routine actually returns the index of the largest (rightmost)
 ** parameter. For all forms except ?NNN, this will correspond to the
 ** number of unique parameters.  If parameters of the ?NNN form are used,
 ** there may be gaps in the list.)^
 **
 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
 ** [sqlite3_bind_parameter_name()], and
 ** [sqlite3_bind_parameter_index()].
 */
 SQLITE_API int sqlite3_bind_parameter_count(sqlite3_stmt*);
 
 /*
 ** CAPI3REF: Name Of A Host Parameter
 ** METHOD: sqlite3_stmt
 **
 ** ^The sqlite3_bind_parameter_name(P,N) interface returns
 ** the name of the N-th [SQL parameter] in the [prepared statement] P.
 ** ^(SQL parameters of the form "?NNN" or ":AAA" or "@AAA" or "$AAA"
 ** have a name which is the string "?NNN" or ":AAA" or "@AAA" or "$AAA"
 ** respectively.
 ** In other words, the initial ":" or "$" or "@" or "?"
 ** is included as part of the name.)^
 ** ^Parameters of the form "?" without a following integer have no name
 ** and are referred to as "nameless" or "anonymous parameters".
 **
 ** ^The first host parameter has an index of 1, not 0.
 **
 ** ^If the value N is out of range or if the N-th parameter is
 ** nameless, then NULL is returned.  ^The returned string is
 ** always in UTF-8 encoding even if the named parameter was
 ** originally specified as UTF-16 in [sqlite3_prepare16()],
 ** [sqlite3_prepare16_v2()], or [sqlite3_prepare16_v3()].
 **
 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
 ** [sqlite3_bind_parameter_count()], and
 ** [sqlite3_bind_parameter_index()].
 */
 SQLITE_API const char *sqlite3_bind_parameter_name(sqlite3_stmt*, int);
 
 /*
 ** CAPI3REF: Index Of A Parameter With A Given Name
 ** METHOD: sqlite3_stmt
 **
 ** ^Return the index of an SQL parameter given its name.  ^The
 ** index value returned is suitable for use as the second
 ** parameter to [sqlite3_bind_blob|sqlite3_bind()].  ^A zero
 ** is returned if no matching parameter is found.  ^The parameter
 ** name must be given in UTF-8 even if the original statement
 ** was prepared from UTF-16 text using [sqlite3_prepare16_v2()] or
 ** [sqlite3_prepare16_v3()].
 **
 ** See also: [sqlite3_bind_blob|sqlite3_bind()],
 ** [sqlite3_bind_parameter_count()], and
 ** [sqlite3_bind_parameter_name()].
 */
 SQLITE_API int sqlite3_bind_parameter_index(sqlite3_stmt*, const char *zName);
 
 /*
 ** CAPI3REF: Reset All Bindings On A Prepared Statement
 ** METHOD: sqlite3_stmt
 **
 ** ^Contrary to the intuition of many, [sqlite3_reset()] does not reset
 ** the [sqlite3_bind_blob | bindings] on a [prepared statement].
 ** ^Use this routine to reset all host parameters to NULL.
 */
 SQLITE_API int sqlite3_clear_bindings(sqlite3_stmt*);
 
 /*
 ** CAPI3REF: Number Of Columns In A Result Set
 ** METHOD: sqlite3_stmt
 **
 ** ^Return the number of columns in the result set returned by the
 ** [prepared statement]. ^If this routine returns 0, that means the 
 ** [prepared statement] returns no data (for example an [UPDATE]).
 ** ^However, just because this routine returns a positive number does not
 ** mean that one or more rows of data will be returned.  ^A SELECT statement
 ** will always have a positive sqlite3_column_count() but depending on the
 ** WHERE clause constraints and the table content, it might return no rows.
 **
 ** See also: [sqlite3_data_count()]
 */
 SQLITE_API int sqlite3_column_count(sqlite3_stmt *pStmt);
 
 /*
 ** CAPI3REF: Column Names In A Result Set
 ** METHOD: sqlite3_stmt
 **
 ** ^These routines return the name assigned to a particular column
 ** in the result set of a [SELECT] statement.  ^The sqlite3_column_name()
 ** interface returns a pointer to a zero-terminated UTF-8 string
 ** and sqlite3_column_name16() returns a pointer to a zero-terminated
 ** UTF-16 string.  ^The first parameter is the [prepared statement]
 ** that implements the [SELECT] statement. ^The second parameter is the
 ** column number.  ^The leftmost column is number 0.
 **
 ** ^The returned string pointer is valid until either the [prepared statement]
 ** is destroyed by [sqlite3_finalize()] or until the statement is automatically
 ** reprepared by the first call to [sqlite3_step()] for a particular run
 ** or until the next call to
 ** sqlite3_column_name() or sqlite3_column_name16() on the same column.
 **
 ** ^If sqlite3_malloc() fails during the processing of either routine
 ** (for example during a conversion from UTF-8 to UTF-16) then a
 ** NULL pointer is returned.
 **
 ** ^The name of a result column is the value of the "AS" clause for
 ** that column, if there is an AS clause.  If there is no AS clause
 ** then the name of the column is unspecified and may change from
 ** one release of SQLite to the next.
 */
 SQLITE_API const char *sqlite3_column_name(sqlite3_stmt*, int N);
 SQLITE_API const void *sqlite3_column_name16(sqlite3_stmt*, int N);
 
 /*
 ** CAPI3REF: Source Of Data In A Query Result
 ** METHOD: sqlite3_stmt
 **
 ** ^These routines provide a means to determine the database, table, and
 ** table column that is the origin of a particular result column in
 ** [SELECT] statement.
 ** ^The name of the database or table or column can be returned as
 ** either a UTF-8 or UTF-16 string.  ^The _database_ routines return
 ** the database name, the _table_ routines return the table name, and
 ** the origin_ routines return the column name.
 ** ^The returned string is valid until the [prepared statement] is destroyed
 ** using [sqlite3_finalize()] or until the statement is automatically
 ** reprepared by the first call to [sqlite3_step()] for a particular run
 ** or until the same information is requested
 ** again in a different encoding.
 **
 ** ^The names returned are the original un-aliased names of the
 ** database, table, and column.
 **
 ** ^The first argument to these interfaces is a [prepared statement].
 ** ^These functions return information about the Nth result column returned by
 ** the statement, where N is the second function argument.
 ** ^The left-most column is column 0 for these routines.
 **
 ** ^If the Nth column returned by the statement is an expression or
 ** subquery and is not a column value, then all of these functions return
 ** NULL.  ^These routine might also return NULL if a memory allocation error
 ** occurs.  ^Otherwise, they return the name of the attached database, table,
 ** or column that query result column was extracted from.
 **
 ** ^As with all other SQLite APIs, those whose names end with "16" return
 ** UTF-16 encoded strings and the other functions return UTF-8.
 **
 ** ^These APIs are only available if the library was compiled with the
 ** [SQLITE_ENABLE_COLUMN_METADATA] C-preprocessor symbol.
 **
 ** If two or more threads call one or more of these routines against the same
 ** prepared statement and column at the same time then the results are
 ** undefined.
 **
 ** If two or more threads call one or more
 ** [sqlite3_column_database_name | column metadata interfaces]
 ** for the same [prepared statement] and result column
 ** at the same time then the results are undefined.
 */
 SQLITE_API const char *sqlite3_column_database_name(sqlite3_stmt*,int);
 SQLITE_API const void *sqlite3_column_database_name16(sqlite3_stmt*,int);
 SQLITE_API const char *sqlite3_column_table_name(sqlite3_stmt*,int);
 SQLITE_API const void *sqlite3_column_table_name16(sqlite3_stmt*,int);
 SQLITE_API const char *sqlite3_column_origin_name(sqlite3_stmt*,int);
 SQLITE_API const void *sqlite3_column_origin_name16(sqlite3_stmt*,int);
 
 /*
 ** CAPI3REF: Declared Datatype Of A Query Result
 ** METHOD: sqlite3_stmt
 **
 ** ^(The first parameter is a [prepared statement].
 ** If this statement is a [SELECT] statement and the Nth column of the
 ** returned result set of that [SELECT] is a table column (not an
 ** expression or subquery) then the declared type of the table
 ** column is returned.)^  ^If the Nth column of the result set is an
 ** expression or subquery, then a NULL pointer is returned.
 ** ^The returned string is always UTF-8 encoded.
 **
 ** ^(For example, given the database schema:
 **
 ** CREATE TABLE t1(c1 VARIANT);
 **
 ** and the following statement to be compiled:
 **
 ** SELECT c1 + 1, c1 FROM t1;
 **
 ** this routine would return the string "VARIANT" for the second result
 ** column (i==1), and a NULL pointer for the first result column (i==0).)^
 **
 ** ^SQLite uses dynamic run-time typing.  ^So just because a column
 ** is declared to contain a particular type does not mean that the
 ** data stored in that column is of the declared type.  SQLite is
 ** strongly typed, but the typing is dynamic not static.  ^Type
 ** is associated with individual values, not with the containers
 ** used to hold those values.
 */
 SQLITE_API const char *sqlite3_column_decltype(sqlite3_stmt*,int);
 SQLITE_API const void *sqlite3_column_decltype16(sqlite3_stmt*,int);
 
 /*
 ** CAPI3REF: Evaluate An SQL Statement
 ** METHOD: sqlite3_stmt
 **
 ** After a [prepared statement] has been prepared using any of
 ** [sqlite3_prepare_v2()], [sqlite3_prepare_v3()], [sqlite3_prepare16_v2()],
 ** or [sqlite3_prepare16_v3()] or one of the legacy
 ** interfaces [sqlite3_prepare()] or [sqlite3_prepare16()], this function
 ** must be called one or more times to evaluate the statement.
 **
 ** The details of the behavior of the sqlite3_step() interface depend
 ** on whether the statement was prepared using the newer "vX" interfaces
 ** [sqlite3_prepare_v3()], [sqlite3_prepare_v2()], [sqlite3_prepare16_v3()],
 ** [sqlite3_prepare16_v2()] or the older legacy
 ** interfaces [sqlite3_prepare()] and [sqlite3_prepare16()].  The use of the
 ** new "vX" interface is recommended for new applications but the legacy
 ** interface will continue to be supported.
 **
 ** ^In the legacy interface, the return value will be either [SQLITE_BUSY],
 ** [SQLITE_DONE], [SQLITE_ROW], [SQLITE_ERROR], or [SQLITE_MISUSE].
 ** ^With the "v2" interface, any of the other [result codes] or
 ** [extended result codes] might be returned as well.
 **
 ** ^[SQLITE_BUSY] means that the database engine was unable to acquire the
 ** database locks it needs to do its job.  ^If the statement is a [COMMIT]
 ** or occurs outside of an explicit transaction, then you can retry the
 ** statement.  If the statement is not a [COMMIT] and occurs within an
 ** explicit transaction then you should rollback the transaction before
 ** continuing.
 **
 ** ^[SQLITE_DONE] means that the statement has finished executing
 ** successfully.  sqlite3_step() should not be called again on this virtual
 ** machine without first calling [sqlite3_reset()] to reset the virtual
 ** machine back to its initial state.
 **
 ** ^If the SQL statement being executed returns any data, then [SQLITE_ROW]
 ** is returned each time a new row of data is ready for processing by the
 ** caller. The values may be accessed using the [column access functions].
 ** sqlite3_step() is called again to retrieve the next row of data.
 **
 ** ^[SQLITE_ERROR] means that a run-time error (such as a constraint
 ** violation) has occurred.  sqlite3_step() should not be called again on
 ** the VM. More information may be found by calling [sqlite3_errmsg()].
 ** ^With the legacy interface, a more specific error code (for example,
 ** [SQLITE_INTERRUPT], [SQLITE_SCHEMA], [SQLITE_CORRUPT], and so forth)
 ** can be obtained by calling [sqlite3_reset()] on the
 ** [prepared statement].  ^In the "v2" interface,
 ** the more specific error code is returned directly by sqlite3_step().
 **
 ** [SQLITE_MISUSE] means that the this routine was called inappropriately.
 ** Perhaps it was called on a [prepared statement] that has
 ** already been [sqlite3_finalize | finalized] or on one that had
 ** previously returned [SQLITE_ERROR] or [SQLITE_DONE].  Or it could
 ** be the case that the same database connection is being used by two or
 ** more threads at the same moment in time.
 **
 ** For all versions of SQLite up to and including 3.6.23.1, a call to
 ** [sqlite3_reset()] was required after sqlite3_step() returned anything
 ** other than [SQLITE_ROW] before any subsequent invocation of
 ** sqlite3_step().  Failure to reset the prepared statement using 
 ** [sqlite3_reset()] would result in an [SQLITE_MISUSE] return from
 ** sqlite3_step().  But after [version 3.6.23.1] ([dateof:3.6.23.1],
 ** sqlite3_step() began
 ** calling [sqlite3_reset()] automatically in this circumstance rather
 ** than returning [SQLITE_MISUSE].  This is not considered a compatibility
 ** break because any application that ever receives an SQLITE_MISUSE error
 ** is broken by definition.  The [SQLITE_OMIT_AUTORESET] compile-time option
 ** can be used to restore the legacy behavior.
 **
 ** <b>Goofy Interface Alert:</b> In the legacy interface, the sqlite3_step()
 ** API always returns a generic error code, [SQLITE_ERROR], following any
 ** error other than [SQLITE_BUSY] and [SQLITE_MISUSE].  You must call
 ** [sqlite3_reset()] or [sqlite3_finalize()] in order to find one of the
 ** specific [error codes] that better describes the error.
 ** We admit that this is a goofy design.  The problem has been fixed
 ** with the "v2" interface.  If you prepare all of your SQL statements
 ** using [sqlite3_prepare_v3()] or [sqlite3_prepare_v2()]
 ** or [sqlite3_prepare16_v2()] or [sqlite3_prepare16_v3()] instead
 ** of the legacy [sqlite3_prepare()] and [sqlite3_prepare16()] interfaces,
 ** then the more specific [error codes] are returned directly
 ** by sqlite3_step().  The use of the "vX" interfaces is recommended.
 */
 SQLITE_API int sqlite3_step(sqlite3_stmt*);
 
 /*
 ** CAPI3REF: Number of columns in a result set
 ** METHOD: sqlite3_stmt
 **
 ** ^The sqlite3_data_count(P) interface returns the number of columns in the
 ** current row of the result set of [prepared statement] P.
 ** ^If prepared statement P does not have results ready to return
 ** (via calls to the [sqlite3_column_int | sqlite3_column_*()] of
 ** interfaces) then sqlite3_data_count(P) returns 0.
 ** ^The sqlite3_data_count(P) routine also returns 0 if P is a NULL pointer.
 ** ^The sqlite3_data_count(P) routine returns 0 if the previous call to
 ** [sqlite3_step](P) returned [SQLITE_DONE].  ^The sqlite3_data_count(P)
 ** will return non-zero if previous call to [sqlite3_step](P) returned
 ** [SQLITE_ROW], except in the case of the [PRAGMA incremental_vacuum]
 ** where it always returns zero since each step of that multi-step
 ** pragma returns 0 columns of data.
 **
 ** See also: [sqlite3_column_count()]
 */
 SQLITE_API int sqlite3_data_count(sqlite3_stmt *pStmt);
 
 /*
 ** CAPI3REF: Fundamental Datatypes
 ** KEYWORDS: SQLITE_TEXT
 **
 ** ^(Every value in SQLite has one of five fundamental datatypes:
 **
 ** <ul>
 ** <li> 64-bit signed integer
 ** <li> 64-bit IEEE floating point number
 ** <li> string
 ** <li> BLOB
 ** <li> NULL
 ** </ul>)^
 **
 ** These constants are codes for each of those types.
 **
 ** Note that the SQLITE_TEXT constant was also used in SQLite version 2
 ** for a completely different meaning.  Software that links against both
 ** SQLite version 2 and SQLite version 3 should use SQLITE3_TEXT, not
 ** SQLITE_TEXT.
 */
 #define SQLITE_INTEGER  1
 #define SQLITE_FLOAT    2
 #define SQLITE_BLOB     4
 #define SQLITE_NULL     5
 #ifdef SQLITE_TEXT
 # undef SQLITE_TEXT
 #else
 # define SQLITE_TEXT     3
 #endif
 #define SQLITE3_TEXT     3
 
 /*
 ** CAPI3REF: Result Values From A Query
 ** KEYWORDS: {column access functions}
 ** METHOD: sqlite3_stmt
 **
 ** <b>Summary:</b>
 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
 ** <tr><td><b>sqlite3_column_blob</b><td>&rarr;<td>BLOB result
 ** <tr><td><b>sqlite3_column_double</b><td>&rarr;<td>REAL result
 ** <tr><td><b>sqlite3_column_int</b><td>&rarr;<td>32-bit INTEGER result
 ** <tr><td><b>sqlite3_column_int64</b><td>&rarr;<td>64-bit INTEGER result
 ** <tr><td><b>sqlite3_column_text</b><td>&rarr;<td>UTF-8 TEXT result
 ** <tr><td><b>sqlite3_column_text16</b><td>&rarr;<td>UTF-16 TEXT result
 ** <tr><td><b>sqlite3_column_value</b><td>&rarr;<td>The result as an 
 ** [sqlite3_value|unprotected sqlite3_value] object.
 ** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
 ** <tr><td><b>sqlite3_column_bytes</b><td>&rarr;<td>Size of a BLOB
 ** or a UTF-8 TEXT result in bytes
 ** <tr><td><b>sqlite3_column_bytes16&nbsp;&nbsp;</b>
 ** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
 ** TEXT in bytes
 ** <tr><td><b>sqlite3_column_type</b><td>&rarr;<td>Default
 ** datatype of the result
 ** </table></blockquote>
 **
 ** <b>Details:</b>
 **
 ** ^These routines return information about a single column of the current
 ** result row of a query.  ^In every case the first argument is a pointer
 ** to the [prepared statement] that is being evaluated (the [sqlite3_stmt*]
 ** that was returned from [sqlite3_prepare_v2()] or one of its variants)
 ** and the second argument is the index of the column for which information
 ** should be returned. ^The leftmost column of the result set has the index 0.
 ** ^The number of columns in the result can be determined using
 ** [sqlite3_column_count()].
 **
 ** If the SQL statement does not currently point to a valid row, or if the
 ** column index is out of range, the result is undefined.
 ** These routines may only be called when the most recent call to
 ** [sqlite3_step()] has returned [SQLITE_ROW] and neither
 ** [sqlite3_reset()] nor [sqlite3_finalize()] have been called subsequently.
 ** If any of these routines are called after [sqlite3_reset()] or
 ** [sqlite3_finalize()] or after [sqlite3_step()] has returned
 ** something other than [SQLITE_ROW], the results are undefined.
 ** If [sqlite3_step()] or [sqlite3_reset()] or [sqlite3_finalize()]
 ** are called from a different thread while any of these routines
 ** are pending, then the results are undefined.
 **
 ** The first six interfaces (_blob, _double, _int, _int64, _text, and _text16)
 ** each return the value of a result column in a specific data format.  If
 ** the result column is not initially in the requested format (for example,
 ** if the query returns an integer but the sqlite3_column_text() interface
 ** is used to extract the value) then an automatic type conversion is performed.
 **
 ** ^The sqlite3_column_type() routine returns the
 ** [SQLITE_INTEGER | datatype code] for the initial data type
 ** of the result column.  ^The returned value is one of [SQLITE_INTEGER],
 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].
 ** The return value of sqlite3_column_type() can be used to decide which
 ** of the first six interface should be used to extract the column value.
 ** The value returned by sqlite3_column_type() is only meaningful if no
 ** automatic type conversions have occurred for the value in question.  
 ** After a type conversion, the result of calling sqlite3_column_type()
 ** is undefined, though harmless.  Future
 ** versions of SQLite may change the behavior of sqlite3_column_type()
 ** following a type conversion.
 **
 ** If the result is a BLOB or a TEXT string, then the sqlite3_column_bytes()
 ** or sqlite3_column_bytes16() interfaces can be used to determine the size
 ** of that BLOB or string.
 **
 ** ^If the result is a BLOB or UTF-8 string then the sqlite3_column_bytes()
 ** routine returns the number of bytes in that BLOB or string.
 ** ^If the result is a UTF-16 string, then sqlite3_column_bytes() converts
 ** the string to UTF-8 and then returns the number of bytes.
 ** ^If the result is a numeric value then sqlite3_column_bytes() uses
 ** [sqlite3_snprintf()] to convert that value to a UTF-8 string and returns
 ** the number of bytes in that string.
 ** ^If the result is NULL, then sqlite3_column_bytes() returns zero.
 **
 ** ^If the result is a BLOB or UTF-16 string then the sqlite3_column_bytes16()
 ** routine returns the number of bytes in that BLOB or string.
 ** ^If the result is a UTF-8 string, then sqlite3_column_bytes16() converts
 ** the string to UTF-16 and then returns the number of bytes.
 ** ^If the result is a numeric value then sqlite3_column_bytes16() uses
 ** [sqlite3_snprintf()] to convert that value to a UTF-16 string and returns
 ** the number of bytes in that string.
 ** ^If the result is NULL, then sqlite3_column_bytes16() returns zero.
 **
 ** ^The values returned by [sqlite3_column_bytes()] and 
 ** [sqlite3_column_bytes16()] do not include the zero terminators at the end
 ** of the string.  ^For clarity: the values returned by
 ** [sqlite3_column_bytes()] and [sqlite3_column_bytes16()] are the number of
 ** bytes in the string, not the number of characters.
 **
 ** ^Strings returned by sqlite3_column_text() and sqlite3_column_text16(),
 ** even empty strings, are always zero-terminated.  ^The return
 ** value from sqlite3_column_blob() for a zero-length BLOB is a NULL pointer.
 **
 ** <b>Warning:</b> ^The object returned by [sqlite3_column_value()] is an
 ** [unprotected sqlite3_value] object.  In a multithreaded environment,
 ** an unprotected sqlite3_value object may only be used safely with
 ** [sqlite3_bind_value()] and [sqlite3_result_value()].
 ** If the [unprotected sqlite3_value] object returned by
 ** [sqlite3_column_value()] is used in any other way, including calls
 ** to routines like [sqlite3_value_int()], [sqlite3_value_text()],
 ** or [sqlite3_value_bytes()], the behavior is not threadsafe.
 ** Hence, the sqlite3_column_value() interface
 ** is normally only useful within the implementation of 
 ** [application-defined SQL functions] or [virtual tables], not within
 ** top-level application code.
 **
 ** The these routines may attempt to convert the datatype of the result.
 ** ^For example, if the internal representation is FLOAT and a text result
 ** is requested, [sqlite3_snprintf()] is used internally to perform the
 ** conversion automatically.  ^(The following table details the conversions
 ** that are applied:
 **
 ** <blockquote>
 ** <table border="1">
 ** <tr><th> Internal<br>Type <th> Requested<br>Type <th>  Conversion
 **
 ** <tr><td>  NULL    <td> INTEGER   <td> Result is 0
 ** <tr><td>  NULL    <td>  FLOAT    <td> Result is 0.0
 ** <tr><td>  NULL    <td>   TEXT    <td> Result is a NULL pointer
 ** <tr><td>  NULL    <td>   BLOB    <td> Result is a NULL pointer
 ** <tr><td> INTEGER  <td>  FLOAT    <td> Convert from integer to float
 ** <tr><td> INTEGER  <td>   TEXT    <td> ASCII rendering of the integer
 ** <tr><td> INTEGER  <td>   BLOB    <td> Same as INTEGER->TEXT
 ** <tr><td>  FLOAT   <td> INTEGER   <td> [CAST] to INTEGER
 ** <tr><td>  FLOAT   <td>   TEXT    <td> ASCII rendering of the float
 ** <tr><td>  FLOAT   <td>   BLOB    <td> [CAST] to BLOB
 ** <tr><td>  TEXT    <td> INTEGER   <td> [CAST] to INTEGER
 ** <tr><td>  TEXT    <td>  FLOAT    <td> [CAST] to REAL
 ** <tr><td>  TEXT    <td>   BLOB    <td> No change
 ** <tr><td>  BLOB    <td> INTEGER   <td> [CAST] to INTEGER
 ** <tr><td>  BLOB    <td>  FLOAT    <td> [CAST] to REAL
 ** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
 ** </table>
 ** </blockquote>)^
 **
 ** Note that when type conversions occur, pointers returned by prior
 ** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
 ** sqlite3_column_text16() may be invalidated.
 ** Type conversions and pointer invalidations might occur
 ** in the following cases:
 **
 ** <ul>
 ** <li> The initial content is a BLOB and sqlite3_column_text() or
 **      sqlite3_column_text16() is called.  A zero-terminator might
 **      need to be added to the string.</li>
 ** <li> The initial content is UTF-8 text and sqlite3_column_bytes16() or
 **      sqlite3_column_text16() is called.  The content must be converted
 **      to UTF-16.</li>
 ** <li> The initial content is UTF-16 text and sqlite3_column_bytes() or
 **      sqlite3_column_text() is called.  The content must be converted
 **      to UTF-8.</li>
 ** </ul>
 **
 ** ^Conversions between UTF-16be and UTF-16le are always done in place and do
 ** not invalidate a prior pointer, though of course the content of the buffer
 ** that the prior pointer references will have been modified.  Other kinds
 ** of conversion are done in place when it is possible, but sometimes they
 ** are not possible and in those cases prior pointers are invalidated.
 **
 ** The safest policy is to invoke these routines
 ** in one of the following ways:
 **
 ** <ul>
 **  <li>sqlite3_column_text() followed by sqlite3_column_bytes()</li>
 **  <li>sqlite3_column_blob() followed by sqlite3_column_bytes()</li>
 **  <li>sqlite3_column_text16() followed by sqlite3_column_bytes16()</li>
 ** </ul>
 **
 ** In other words, you should call sqlite3_column_text(),
 ** sqlite3_column_blob(), or sqlite3_column_text16() first to force the result
 ** into the desired format, then invoke sqlite3_column_bytes() or
 ** sqlite3_column_bytes16() to find the size of the result.  Do not mix calls
 ** to sqlite3_column_text() or sqlite3_column_blob() with calls to
 ** sqlite3_column_bytes16(), and do not mix calls to sqlite3_column_text16()
 ** with calls to sqlite3_column_bytes().
 **
 ** ^The pointers returned are valid until a type conversion occurs as
 ** described above, or until [sqlite3_step()] or [sqlite3_reset()] or
 ** [sqlite3_finalize()] is called.  ^The memory space used to hold strings
 ** and BLOBs is freed automatically.  Do not pass the pointers returned
 ** from [sqlite3_column_blob()], [sqlite3_column_text()], etc. into
 ** [sqlite3_free()].
 **
 ** ^(If a memory allocation error occurs during the evaluation of any
 ** of these routines, a default value is returned.  The default value
 ** is either the integer 0, the floating point number 0.0, or a NULL
 ** pointer.  Subsequent calls to [sqlite3_errcode()] will return
 ** [SQLITE_NOMEM].)^
 */
 SQLITE_API const void *sqlite3_column_blob(sqlite3_stmt*, int iCol);
 SQLITE_API double sqlite3_column_double(sqlite3_stmt*, int iCol);
 SQLITE_API int sqlite3_column_int(sqlite3_stmt*, int iCol);
 SQLITE_API sqlite3_int64 sqlite3_column_int64(sqlite3_stmt*, int iCol);
 SQLITE_API const unsigned char *sqlite3_column_text(sqlite3_stmt*, int iCol);
 SQLITE_API const void *sqlite3_column_text16(sqlite3_stmt*, int iCol);
 SQLITE_API sqlite3_value *sqlite3_column_value(sqlite3_stmt*, int iCol);
 SQLITE_API int sqlite3_column_bytes(sqlite3_stmt*, int iCol);
 SQLITE_API int sqlite3_column_bytes16(sqlite3_stmt*, int iCol);
 SQLITE_API int sqlite3_column_type(sqlite3_stmt*, int iCol);
 
 /*
 ** CAPI3REF: Destroy A Prepared Statement Object
 ** DESTRUCTOR: sqlite3_stmt
 **
 ** ^The sqlite3_finalize() function is called to delete a [prepared statement].
 ** ^If the most recent evaluation of the statement encountered no errors
 ** or if the statement is never been evaluated, then sqlite3_finalize() returns
 ** SQLITE_OK.  ^If the most recent evaluation of statement S failed, then
 ** sqlite3_finalize(S) returns the appropriate [error code] or
 ** [extended error code].
 **
 ** ^The sqlite3_finalize(S) routine can be called at any point during
 ** the life cycle of [prepared statement] S:
 ** before statement S is ever evaluated, after
 ** one or more calls to [sqlite3_reset()], or after any call
 ** to [sqlite3_step()] regardless of whether or not the statement has
 ** completed execution.
 **
 ** ^Invoking sqlite3_finalize() on a NULL pointer is a harmless no-op.
 **
 ** The application must finalize every [prepared statement] in order to avoid
 ** resource leaks.  It is a grievous error for the application to try to use
 ** a prepared statement after it has been finalized.  Any use of a prepared
 ** statement after it has been finalized can result in undefined and
 ** undesirable behavior such as segfaults and heap corruption.
 */
 SQLITE_API int sqlite3_finalize(sqlite3_stmt *pStmt);
 
 /*
 ** CAPI3REF: Reset A Prepared Statement Object
 ** METHOD: sqlite3_stmt
 **
 ** The sqlite3_reset() function is called to reset a [prepared statement]
 ** object back to its initial state, ready to be re-executed.
 ** ^Any SQL statement variables that had values bound to them using
 ** the [sqlite3_bind_blob | sqlite3_bind_*() API] retain their values.
 ** Use [sqlite3_clear_bindings()] to reset the bindings.
 **
 ** ^The [sqlite3_reset(S)] interface resets the [prepared statement] S
 ** back to the beginning of its program.
 **
 ** ^If the most recent call to [sqlite3_step(S)] for the
 ** [prepared statement] S returned [SQLITE_ROW] or [SQLITE_DONE],
 ** or if [sqlite3_step(S)] has never before been called on S,
 ** then [sqlite3_reset(S)] returns [SQLITE_OK].
 **
 ** ^If the most recent call to [sqlite3_step(S)] for the
 ** [prepared statement] S indicated an error, then
 ** [sqlite3_reset(S)] returns an appropriate [error code].
 **
 ** ^The [sqlite3_reset(S)] interface does not change the values
 ** of any [sqlite3_bind_blob|bindings] on the [prepared statement] S.
 */
 SQLITE_API int sqlite3_reset(sqlite3_stmt *pStmt);
 
 /*
 ** CAPI3REF: Create Or Redefine SQL Functions
 ** KEYWORDS: {function creation routines}
 ** KEYWORDS: {application-defined SQL function}
 ** KEYWORDS: {application-defined SQL functions}
 ** METHOD: sqlite3
 **
 ** ^These functions (collectively known as "function creation routines")
 ** are used to add SQL functions or aggregates or to redefine the behavior
 ** of existing SQL functions or aggregates.  The only differences between
 ** these routines are the text encoding expected for
 ** the second parameter (the name of the function being created)
 ** and the presence or absence of a destructor callback for
 ** the application data pointer.
 **
 ** ^The first parameter is the [database connection] to which the SQL
 ** function is to be added.  ^If an application uses more than one database
 ** connection then application-defined SQL functions must be added
 ** to each database connection separately.
 **
 ** ^The second parameter is the name of the SQL function to be created or
 ** redefined.  ^The length of the name is limited to 255 bytes in a UTF-8
 ** representation, exclusive of the zero-terminator.  ^Note that the name
 ** length limit is in UTF-8 bytes, not characters nor UTF-16 bytes.  
 ** ^Any attempt to create a function with a longer name
 ** will result in [SQLITE_MISUSE] being returned.
 **
 ** ^The third parameter (nArg)
 ** is the number of arguments that the SQL function or
 ** aggregate takes. ^If this parameter is -1, then the SQL function or
 ** aggregate may take any number of arguments between 0 and the limit
 ** set by [sqlite3_limit]([SQLITE_LIMIT_FUNCTION_ARG]).  If the third
 ** parameter is less than -1 or greater than 127 then the behavior is
 ** undefined.
 **
 ** ^The fourth parameter, eTextRep, specifies what
 ** [SQLITE_UTF8 | text encoding] this SQL function prefers for
 ** its parameters.  The application should set this parameter to
 ** [SQLITE_UTF16LE] if the function implementation invokes 
 ** [sqlite3_value_text16le()] on an input, or [SQLITE_UTF16BE] if the
 ** implementation invokes [sqlite3_value_text16be()] on an input, or
 ** [SQLITE_UTF16] if [sqlite3_value_text16()] is used, or [SQLITE_UTF8]
 ** otherwise.  ^The same SQL function may be registered multiple times using
 ** different preferred text encodings, with different implementations for
 ** each encoding.
 ** ^When multiple implementations of the same function are available, SQLite
 ** will pick the one that involves the least amount of data conversion.
 **
 ** ^The fourth parameter may optionally be ORed with [SQLITE_DETERMINISTIC]
 ** to signal that the function will always return the same result given
 ** the same inputs within a single SQL statement.  Most SQL functions are
 ** deterministic.  The built-in [random()] SQL function is an example of a
 ** function that is not deterministic.  The SQLite query planner is able to
 ** perform additional optimizations on deterministic functions, so use
 ** of the [SQLITE_DETERMINISTIC] flag is recommended where possible.
 **
 ** ^(The fifth parameter is an arbitrary pointer.  The implementation of the
 ** function can gain access to this pointer using [sqlite3_user_data()].)^
 **
 ** ^The sixth, seventh and eighth parameters, xFunc, xStep and xFinal, are
 ** pointers to C-language functions that implement the SQL function or
 ** aggregate. ^A scalar SQL function requires an implementation of the xFunc
 ** callback only; NULL pointers must be passed as the xStep and xFinal
 ** parameters. ^An aggregate SQL function requires an implementation of xStep
 ** and xFinal and NULL pointer must be passed for xFunc. ^To delete an existing
 ** SQL function or aggregate, pass NULL pointers for all three function
 ** callbacks.
 **
 ** ^(If the ninth parameter to sqlite3_create_function_v2() is not NULL,
 ** then it is destructor for the application data pointer. 
 ** The destructor is invoked when the function is deleted, either by being
 ** overloaded or when the database connection closes.)^
 ** ^The destructor is also invoked if the call to
 ** sqlite3_create_function_v2() fails.
 ** ^When the destructor callback of the tenth parameter is invoked, it
 ** is passed a single argument which is a copy of the application data 
 ** pointer which was the fifth parameter to sqlite3_create_function_v2().
 **
 ** ^It is permitted to register multiple implementations of the same
 ** functions with the same name but with either differing numbers of
 ** arguments or differing preferred text encodings.  ^SQLite will use
 ** the implementation that most closely matches the way in which the
 ** SQL function is used.  ^A function implementation with a non-negative
 ** nArg parameter is a better match than a function implementation with
 ** a negative nArg.  ^A function where the preferred text encoding
 ** matches the database encoding is a better
 ** match than a function where the encoding is different.  
 ** ^A function where the encoding difference is between UTF16le and UTF16be
 ** is a closer match than a function where the encoding difference is
 ** between UTF8 and UTF16.
 **
 ** ^Built-in functions may be overloaded by new application-defined functions.
 **
 ** ^An application-defined function is permitted to call other
 ** SQLite interfaces.  However, such calls must not
 ** close the database connection nor finalize or reset the prepared
 ** statement in which the function is running.
 */
 SQLITE_API int sqlite3_create_function(
   sqlite3 *db,
   const char *zFunctionName,
   int nArg,
   int eTextRep,
   void *pApp,
   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
   void (*xFinal)(sqlite3_context*)
 );
 SQLITE_API int sqlite3_create_function16(
   sqlite3 *db,
   const void *zFunctionName,
   int nArg,
   int eTextRep,
   void *pApp,
   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
   void (*xFinal)(sqlite3_context*)
 );
 SQLITE_API int sqlite3_create_function_v2(
   sqlite3 *db,
   const char *zFunctionName,
   int nArg,
   int eTextRep,
   void *pApp,
   void (*xFunc)(sqlite3_context*,int,sqlite3_value**),
   void (*xStep)(sqlite3_context*,int,sqlite3_value**),
   void (*xFinal)(sqlite3_context*),
   void(*xDestroy)(void*)
 );
 
 /*
 ** CAPI3REF: Text Encodings
 **
 ** These constant define integer codes that represent the various
 ** text encodings supported by SQLite.
 */
 #define SQLITE_UTF8           1    /* IMP: R-37514-35566 */
 #define SQLITE_UTF16LE        2    /* IMP: R-03371-37637 */
 #define SQLITE_UTF16BE        3    /* IMP: R-51971-34154 */
 #define SQLITE_UTF16          4    /* Use native byte order */
 #define SQLITE_ANY            5    /* Deprecated */
 #define SQLITE_UTF16_ALIGNED  8    /* sqlite3_create_collation only */
 
 /*
 ** CAPI3REF: Function Flags
 **
 ** These constants may be ORed together with the 
 ** [SQLITE_UTF8 | preferred text encoding] as the fourth argument
 ** to [sqlite3_create_function()], [sqlite3_create_function16()], or
 ** [sqlite3_create_function_v2()].
 */
 #define SQLITE_DETERMINISTIC    0x800
 
 /*
 ** CAPI3REF: Deprecated Functions
 ** DEPRECATED
 **
 ** These functions are [deprecated].  In order to maintain
 ** backwards compatibility with older code, these functions continue 
 ** to be supported.  However, new applications should avoid
 ** the use of these functions.  To encourage programmers to avoid
 ** these functions, we will not explain what they do.
 */
 #ifndef SQLITE_OMIT_DEPRECATED
 SQLITE_API SQLITE_DEPRECATED int sqlite3_aggregate_count(sqlite3_context*);
 SQLITE_API SQLITE_DEPRECATED int sqlite3_expired(sqlite3_stmt*);
 SQLITE_API SQLITE_DEPRECATED int sqlite3_transfer_bindings(sqlite3_stmt*, sqlite3_stmt*);
 SQLITE_API SQLITE_DEPRECATED int sqlite3_global_recover(void);
 SQLITE_API SQLITE_DEPRECATED void sqlite3_thread_cleanup(void);
 SQLITE_API SQLITE_DEPRECATED int sqlite3_memory_alarm(void(*)(void*,sqlite3_int64,int),
                       void*,sqlite3_int64);
 #endif
 
 /*
 ** CAPI3REF: Obtaining SQL Values
 ** METHOD: sqlite3_value
 **
 ** <b>Summary:</b>
 ** <blockquote><table border=0 cellpadding=0 cellspacing=0>
 ** <tr><td><b>sqlite3_value_blob</b><td>&rarr;<td>BLOB value
 ** <tr><td><b>sqlite3_value_double</b><td>&rarr;<td>REAL value
 ** <tr><td><b>sqlite3_value_int</b><td>&rarr;<td>32-bit INTEGER value
 ** <tr><td><b>sqlite3_value_int64</b><td>&rarr;<td>64-bit INTEGER value
 ** <tr><td><b>sqlite3_value_pointer</b><td>&rarr;<td>Pointer value
 ** <tr><td><b>sqlite3_value_text</b><td>&rarr;<td>UTF-8 TEXT value
 ** <tr><td><b>sqlite3_value_text16</b><td>&rarr;<td>UTF-16 TEXT value in
 ** the native byteorder
 ** <tr><td><b>sqlite3_value_text16be</b><td>&rarr;<td>UTF-16be TEXT value
 ** <tr><td><b>sqlite3_value_text16le</b><td>&rarr;<td>UTF-16le TEXT value
 ** <tr><td>&nbsp;<td>&nbsp;<td>&nbsp;
 ** <tr><td><b>sqlite3_value_bytes</b><td>&rarr;<td>Size of a BLOB
 ** or a UTF-8 TEXT in bytes
 ** <tr><td><b>sqlite3_value_bytes16&nbsp;&nbsp;</b>
 ** <td>&rarr;&nbsp;&nbsp;<td>Size of UTF-16
 ** TEXT in bytes
 ** <tr><td><b>sqlite3_value_type</b><td>&rarr;<td>Default
 ** datatype of the value
 ** <tr><td><b>sqlite3_value_numeric_type&nbsp;&nbsp;</b>
 ** <td>&rarr;&nbsp;&nbsp;<td>Best numeric datatype of the value
 ** <tr><td><b>sqlite3_value_nochange&nbsp;&nbsp;</b>
 ** <td>&rarr;&nbsp;&nbsp;<td>True if the column is unchanged in an UPDATE
 ** against a virtual table.
 ** </table></blockquote>
 **
 ** <b>Details:</b>
 **
 ** These routines extract type, size, and content information from
 ** [protected sqlite3_value] objects.  Protected sqlite3_value objects
 ** are used to pass parameter information into implementation of
 ** [application-defined SQL functions] and [virtual tables].
 **
 ** These routines work only with [protected sqlite3_value] objects.
 ** Any attempt to use these routines on an [unprotected sqlite3_value]
 ** is not threadsafe.
 **
 ** ^These routines work just like the corresponding [column access functions]
 ** except that these routines take a single [protected sqlite3_value] object
 ** pointer instead of a [sqlite3_stmt*] pointer and an integer column number.
 **
 ** ^The sqlite3_value_text16() interface extracts a UTF-16 string
 ** in the native byte-order of the host machine.  ^The
 ** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
 ** extract UTF-16 strings as big-endian and little-endian respectively.
 **
 ** ^If [sqlite3_value] object V was initialized 
 ** using [sqlite3_bind_pointer(S,I,P,X,D)] or [sqlite3_result_pointer(C,P,X,D)]
 ** and if X and Y are strings that compare equal according to strcmp(X,Y),
 ** then sqlite3_value_pointer(V,Y) will return the pointer P.  ^Otherwise,
 ** sqlite3_value_pointer(V,Y) returns a NULL. The sqlite3_bind_pointer() 
 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
 **
 ** ^(The sqlite3_value_type(V) interface returns the
 ** [SQLITE_INTEGER | datatype code] for the initial datatype of the
 ** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
 ** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
 ** Other interfaces might change the datatype for an sqlite3_value object.
 ** For example, if the datatype is initially SQLITE_INTEGER and
 ** sqlite3_value_text(V) is called to extract a text value for that
 ** integer, then subsequent calls to sqlite3_value_type(V) might return
 ** SQLITE_TEXT.  Whether or not a persistent internal datatype conversion
 ** occurs is undefined and may change from one release of SQLite to the next.
 **
 ** ^(The sqlite3_value_numeric_type() interface attempts to apply
 ** numeric affinity to the value.  This means that an attempt is
 ** made to convert the value to an integer or floating point.  If
 ** such a conversion is possible without loss of information (in other
 ** words, if the value is a string that looks like a number)
 ** then the conversion is performed.  Otherwise no conversion occurs.
 ** The [SQLITE_INTEGER | datatype] after conversion is returned.)^
 **
 ** ^Within the [xUpdate] method of a [virtual table], the
 ** sqlite3_value_nochange(X) interface returns true if and only if
 ** the column corresponding to X is unchanged by the UPDATE operation
 ** that the xUpdate method call was invoked to implement and if
 ** and the prior [xColumn] method call that was invoked to extracted
 ** the value for that column returned without setting a result (probably
 ** because it queried [sqlite3_vtab_nochange()] and found that the column
 ** was unchanging).  ^Within an [xUpdate] method, any value for which
 ** sqlite3_value_nochange(X) is true will in all other respects appear
 ** to be a NULL value.  If sqlite3_value_nochange(X) is invoked anywhere other
 ** than within an [xUpdate] method call for an UPDATE statement, then
 ** the return value is arbitrary and meaningless.
 **
 ** Please pay particular attention to the fact that the pointer returned
 ** from [sqlite3_value_blob()], [sqlite3_value_text()], or
 ** [sqlite3_value_text16()] can be invalidated by a subsequent call to
 ** [sqlite3_value_bytes()], [sqlite3_value_bytes16()], [sqlite3_value_text()],
 ** or [sqlite3_value_text16()].
 **
 ** These routines must be called from the same thread as
 ** the SQL function that supplied the [sqlite3_value*] parameters.
 */
 SQLITE_API const void *sqlite3_value_blob(sqlite3_value*);
 SQLITE_API double sqlite3_value_double(sqlite3_value*);
 SQLITE_API int sqlite3_value_int(sqlite3_value*);
 SQLITE_API sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
 SQLITE_API void *sqlite3_value_pointer(sqlite3_value*, const char*);
 SQLITE_API const unsigned char *sqlite3_value_text(sqlite3_value*);
 SQLITE_API const void *sqlite3_value_text16(sqlite3_value*);
 SQLITE_API const void *sqlite3_value_text16le(sqlite3_value*);
 SQLITE_API const void *sqlite3_value_text16be(sqlite3_value*);
 SQLITE_API int sqlite3_value_bytes(sqlite3_value*);
 SQLITE_API int sqlite3_value_bytes16(sqlite3_value*);
 SQLITE_API int sqlite3_value_type(sqlite3_value*);
 SQLITE_API int sqlite3_value_numeric_type(sqlite3_value*);
 SQLITE_API int sqlite3_value_nochange(sqlite3_value*);
 
 /*
 ** CAPI3REF: Finding The Subtype Of SQL Values
 ** METHOD: sqlite3_value
 **
 ** The sqlite3_value_subtype(V) function returns the subtype for
 ** an [application-defined SQL function] argument V.  The subtype
 ** information can be used to pass a limited amount of context from
 ** one SQL function to another.  Use the [sqlite3_result_subtype()]
 ** routine to set the subtype for the return value of an SQL function.
 */
 SQLITE_API unsigned int sqlite3_value_subtype(sqlite3_value*);
 
 /*
 ** CAPI3REF: Copy And Free SQL Values
 ** METHOD: sqlite3_value
 **
 ** ^The sqlite3_value_dup(V) interface makes a copy of the [sqlite3_value]
 ** object D and returns a pointer to that copy.  ^The [sqlite3_value] returned
 ** is a [protected sqlite3_value] object even if the input is not.
 ** ^The sqlite3_value_dup(V) interface returns NULL if V is NULL or if a
 ** memory allocation fails.
 **
 ** ^The sqlite3_value_free(V) interface frees an [sqlite3_value] object
 ** previously obtained from [sqlite3_value_dup()].  ^If V is a NULL pointer
 ** then sqlite3_value_free(V) is a harmless no-op.
 */
 SQLITE_API sqlite3_value *sqlite3_value_dup(const sqlite3_value*);
 SQLITE_API void sqlite3_value_free(sqlite3_value*);
 
 /*
 ** CAPI3REF: Obtain Aggregate Function Context
 ** METHOD: sqlite3_context
 **
 ** Implementations of aggregate SQL functions use this
 ** routine to allocate memory for storing their state.
 **
 ** ^The first time the sqlite3_aggregate_context(C,N) routine is called 
 ** for a particular aggregate function, SQLite
 ** allocates N of memory, zeroes out that memory, and returns a pointer
 ** to the new memory. ^On second and subsequent calls to
 ** sqlite3_aggregate_context() for the same aggregate function instance,
 ** the same buffer is returned.  Sqlite3_aggregate_context() is normally
 ** called once for each invocation of the xStep callback and then one
 ** last time when the xFinal callback is invoked.  ^(When no rows match
 ** an aggregate query, the xStep() callback of the aggregate function
 ** implementation is never called and xFinal() is called exactly once.
 ** In those cases, sqlite3_aggregate_context() might be called for the
 ** first time from within xFinal().)^
 **
 ** ^The sqlite3_aggregate_context(C,N) routine returns a NULL pointer 
 ** when first called if N is less than or equal to zero or if a memory
 ** allocate error occurs.
 **
 ** ^(The amount of space allocated by sqlite3_aggregate_context(C,N) is
 ** determined by the N parameter on first successful call.  Changing the
 ** value of N in subsequent call to sqlite3_aggregate_context() within
 ** the same aggregate function instance will not resize the memory
 ** allocation.)^  Within the xFinal callback, it is customary to set
 ** N=0 in calls to sqlite3_aggregate_context(C,N) so that no 
 ** pointless memory allocations occur.
 **
 ** ^SQLite automatically frees the memory allocated by 
 ** sqlite3_aggregate_context() when the aggregate query concludes.
 **
 ** The first parameter must be a copy of the
 ** [sqlite3_context | SQL function context] that is the first parameter
 ** to the xStep or xFinal callback routine that implements the aggregate
 ** function.
 **
 ** This routine must be called from the same thread in which
 ** the aggregate SQL function is running.
 */
 SQLITE_API void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);
 
 /*
 ** CAPI3REF: User Data For Functions
 ** METHOD: sqlite3_context
 **
 ** ^The sqlite3_user_data() interface returns a copy of
 ** the pointer that was the pUserData parameter (the 5th parameter)
 ** of the [sqlite3_create_function()]
 ** and [sqlite3_create_function16()] routines that originally
 ** registered the application defined function.
 **
 ** This routine must be called from the same thread in which
 ** the application-defined function is running.
 */
 SQLITE_API void *sqlite3_user_data(sqlite3_context*);
 
 /*
 ** CAPI3REF: Database Connection For Functions
 ** METHOD: sqlite3_context
 **
 ** ^The sqlite3_context_db_handle() interface returns a copy of
 ** the pointer to the [database connection] (the 1st parameter)
 ** of the [sqlite3_create_function()]
 ** and [sqlite3_create_function16()] routines that originally
 ** registered the application defined function.
 */
 SQLITE_API sqlite3 *sqlite3_context_db_handle(sqlite3_context*);
 
 /*
 ** CAPI3REF: Function Auxiliary Data
 ** METHOD: sqlite3_context
 **
 ** These functions may be used by (non-aggregate) SQL functions to
 ** associate metadata with argument values. If the same value is passed to
 ** multiple invocations of the same SQL function during query execution, under
 ** some circumstances the associated metadata may be preserved.  An example
 ** of where this might be useful is in a regular-expression matching
 ** function. The compiled version of the regular expression can be stored as
 ** metadata associated with the pattern string.  
 ** Then as long as the pattern string remains the same,
 ** the compiled regular expression can be reused on multiple
 ** invocations of the same function.
 **
 ** ^The sqlite3_get_auxdata(C,N) interface returns a pointer to the metadata
 ** associated by the sqlite3_set_auxdata(C,N,P,X) function with the Nth argument
 ** value to the application-defined function.  ^N is zero for the left-most
 ** function argument.  ^If there is no metadata
 ** associated with the function argument, the sqlite3_get_auxdata(C,N) interface
 ** returns a NULL pointer.
 **
 ** ^The sqlite3_set_auxdata(C,N,P,X) interface saves P as metadata for the N-th
 ** argument of the application-defined function.  ^Subsequent
 ** calls to sqlite3_get_auxdata(C,N) return P from the most recent
 ** sqlite3_set_auxdata(C,N,P,X) call if the metadata is still valid or
 ** NULL if the metadata has been discarded.
 ** ^After each call to sqlite3_set_auxdata(C,N,P,X) where X is not NULL,
 ** SQLite will invoke the destructor function X with parameter P exactly
 ** once, when the metadata is discarded.
 ** SQLite is free to discard the metadata at any time, including: <ul>
 ** <li> ^(when the corresponding function parameter changes)^, or
 ** <li> ^(when [sqlite3_reset()] or [sqlite3_finalize()] is called for the
 **      SQL statement)^, or
 ** <li> ^(when sqlite3_set_auxdata() is invoked again on the same
 **       parameter)^, or
 ** <li> ^(during the original sqlite3_set_auxdata() call when a memory 
 **      allocation error occurs.)^ </ul>
 **
 ** Note the last bullet in particular.  The destructor X in 
 ** sqlite3_set_auxdata(C,N,P,X) might be called immediately, before the
 ** sqlite3_set_auxdata() interface even returns.  Hence sqlite3_set_auxdata()
 ** should be called near the end of the function implementation and the
 ** function implementation should not make any use of P after
 ** sqlite3_set_auxdata() has been called.
 **
 ** ^(In practice, metadata is preserved between function calls for
 ** function parameters that are compile-time constants, including literal
 ** values and [parameters] and expressions composed from the same.)^
 **
 ** The value of the N parameter to these interfaces should be non-negative.
 ** Future enhancements may make use of negative N values to define new
 ** kinds of function caching behavior.
 **
 ** These routines must be called from the same thread in which
 ** the SQL function is running.
 */
 SQLITE_API void *sqlite3_get_auxdata(sqlite3_context*, int N);
 SQLITE_API void sqlite3_set_auxdata(sqlite3_context*, int N, void*, void (*)(void*));
 
 
 /*
 ** CAPI3REF: Constants Defining Special Destructor Behavior
 **
 ** These are special values for the destructor that is passed in as the
 ** final argument to routines like [sqlite3_result_blob()].  ^If the destructor
 ** argument is SQLITE_STATIC, it means that the content pointer is constant
 ** and will never change.  It does not need to be destroyed.  ^The
 ** SQLITE_TRANSIENT value means that the content will likely change in
 ** the near future and that SQLite should make its own private copy of
 ** the content before returning.
 **
 ** The typedef is necessary to work around problems in certain
 ** C++ compilers.
 */
 typedef void (*sqlite3_destructor_type)(void*);
 #define SQLITE_STATIC      ((sqlite3_destructor_type)0)
 #define SQLITE_TRANSIENT   ((sqlite3_destructor_type)-1)
 
 /*
 ** CAPI3REF: Setting The Result Of An SQL Function
 ** METHOD: sqlite3_context
 **
 ** These routines are used by the xFunc or xFinal callbacks that
 ** implement SQL functions and aggregates.  See
 ** [sqlite3_create_function()] and [sqlite3_create_function16()]
 ** for additional information.
 **
 ** These functions work very much like the [parameter binding] family of
 ** functions used to bind values to host parameters in prepared statements.
 ** Refer to the [SQL parameter] documentation for additional information.
 **
 ** ^The sqlite3_result_blob() interface sets the result from
 ** an application-defined function to be the BLOB whose content is pointed
 ** to by the second parameter and which is N bytes long where N is the
 ** third parameter.
 **
 ** ^The sqlite3_result_zeroblob(C,N) and sqlite3_result_zeroblob64(C,N)
 ** interfaces set the result of the application-defined function to be
 ** a BLOB containing all zero bytes and N bytes in size.
 **
 ** ^The sqlite3_result_double() interface sets the result from
 ** an application-defined function to be a floating point value specified
 ** by its 2nd argument.
 **
 ** ^The sqlite3_result_error() and sqlite3_result_error16() functions
 ** cause the implemented SQL function to throw an exception.
 ** ^SQLite uses the string pointed to by the
 ** 2nd parameter of sqlite3_result_error() or sqlite3_result_error16()
 ** as the text of an error message.  ^SQLite interprets the error
 ** message string from sqlite3_result_error() as UTF-8. ^SQLite
 ** interprets the string from sqlite3_result_error16() as UTF-16 in native
 ** byte order.  ^If the third parameter to sqlite3_result_error()
 ** or sqlite3_result_error16() is negative then SQLite takes as the error
 ** message all text up through the first zero character.
 ** ^If the third parameter to sqlite3_result_error() or
 ** sqlite3_result_error16() is non-negative then SQLite takes that many
 ** bytes (not characters) from the 2nd parameter as the error message.
 ** ^The sqlite3_result_error() and sqlite3_result_error16()
 ** routines make a private copy of the error message text before
 ** they return.  Hence, the calling function can deallocate or
 ** modify the text after they return without harm.
 ** ^The sqlite3_result_error_code() function changes the error code
 ** returned by SQLite as a result of an error in a function.  ^By default,
 ** the error code is SQLITE_ERROR.  ^A subsequent call to sqlite3_result_error()
 ** or sqlite3_result_error16() resets the error code to SQLITE_ERROR.
 **
 ** ^The sqlite3_result_error_toobig() interface causes SQLite to throw an
 ** error indicating that a string or BLOB is too long to represent.
 **
 ** ^The sqlite3_result_error_nomem() interface causes SQLite to throw an
 ** error indicating that a memory allocation failed.
 **
 ** ^The sqlite3_result_int() interface sets the return value
 ** of the application-defined function to be the 32-bit signed integer
 ** value given in the 2nd argument.
 ** ^The sqlite3_result_int64() interface sets the return value
 ** of the application-defined function to be the 64-bit signed integer
 ** value given in the 2nd argument.
 **
 ** ^The sqlite3_result_null() interface sets the return value
 ** of the application-defined function to be NULL.
 **
 ** ^The sqlite3_result_text(), sqlite3_result_text16(),
 ** sqlite3_result_text16le(), and sqlite3_result_text16be() interfaces
 ** set the return value of the application-defined function to be
 ** a text string which is represented as UTF-8, UTF-16 native byte order,
 ** UTF-16 little endian, or UTF-16 big endian, respectively.
 ** ^The sqlite3_result_text64() interface sets the return value of an
 ** application-defined function to be a text string in an encoding
 ** specified by the fifth (and last) parameter, which must be one
 ** of [SQLITE_UTF8], [SQLITE_UTF16], [SQLITE_UTF16BE], or [SQLITE_UTF16LE].
 ** ^SQLite takes the text result from the application from
 ** the 2nd parameter of the sqlite3_result_text* interfaces.
 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
 ** is negative, then SQLite takes result text from the 2nd parameter
 ** through the first zero character.
 ** ^If the 3rd parameter to the sqlite3_result_text* interfaces
 ** is non-negative, then as many bytes (not characters) of the text
 ** pointed to by the 2nd parameter are taken as the application-defined
 ** function result.  If the 3rd parameter is non-negative, then it
 ** must be the byte offset into the string where the NUL terminator would
 ** appear if the string where NUL terminated.  If any NUL characters occur
 ** in the string at a byte offset that is less than the value of the 3rd
 ** parameter, then the resulting string will contain embedded NULs and the
 ** result of expressions operating on strings with embedded NULs is undefined.
 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
 ** or sqlite3_result_blob is a non-NULL pointer, then SQLite calls that
 ** function as the destructor on the text or BLOB result when it has
 ** finished using that result.
 ** ^If the 4th parameter to the sqlite3_result_text* interfaces or to
 ** sqlite3_result_blob is the special constant SQLITE_STATIC, then SQLite
 ** assumes that the text or BLOB result is in constant space and does not
 ** copy the content of the parameter nor call a destructor on the content
 ** when it has finished using that result.
 ** ^If the 4th parameter to the sqlite3_result_text* interfaces
 ** or sqlite3_result_blob is the special constant SQLITE_TRANSIENT
 ** then SQLite makes a copy of the result into space obtained
 ** from [sqlite3_malloc()] before it returns.
 **
 ** ^The sqlite3_result_value() interface sets the result of
 ** the application-defined function to be a copy of the
 ** [unprotected sqlite3_value] object specified by the 2nd parameter.  ^The
 ** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
 ** so that the [sqlite3_value] specified in the parameter may change or
 ** be deallocated after sqlite3_result_value() returns without harm.
 ** ^A [protected sqlite3_value] object may always be used where an
 ** [unprotected sqlite3_value] object is required, so either
 ** kind of [sqlite3_value] object can be used with this interface.
 **
 ** ^The sqlite3_result_pointer(C,P,T,D) interface sets the result to an
 ** SQL NULL value, just like [sqlite3_result_null(C)], except that it
 ** also associates the host-language pointer P or type T with that 
 ** NULL value such that the pointer can be retrieved within an
 ** [application-defined SQL function] using [sqlite3_value_pointer()].
 ** ^If the D parameter is not NULL, then it is a pointer to a destructor
 ** for the P parameter.  ^SQLite invokes D with P as its only argument
 ** when SQLite is finished with P.  The T parameter should be a static
 ** string and preferably a string literal. The sqlite3_result_pointer()
 ** routine is part of the [pointer passing interface] added for SQLite 3.20.0.
 **
 ** If these routines are called from within the different thread
 ** than the one containing the application-defined function that received
 ** the [sqlite3_context] pointer, the results are undefined.
 */
 SQLITE_API void sqlite3_result_blob(sqlite3_context*, const void*, int, void(*)(void*));
 SQLITE_API void sqlite3_result_blob64(sqlite3_context*,const void*,
                            sqlite3_uint64,void(*)(void*));
 SQLITE_API void sqlite3_result_double(sqlite3_context*, double);
 SQLITE_API void sqlite3_result_error(sqlite3_context*, const char*, int);
 SQLITE_API void sqlite3_result_error16(sqlite3_context*, const void*, int);
 SQLITE_API void sqlite3_result_error_toobig(sqlite3_context*);
 SQLITE_API void sqlite3_result_error_nomem(sqlite3_context*);
 SQLITE_API void sqlite3_result_error_code(sqlite3_context*, int);
 SQLITE_API void sqlite3_result_int(sqlite3_context*, int);
 SQLITE_API void sqlite3_result_int64(sqlite3_context*, sqlite3_int64);
 SQLITE_API void sqlite3_result_null(sqlite3_context*);
 SQLITE_API void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
 SQLITE_API void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
                            void(*)(void*), unsigned char encoding);
 SQLITE_API void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
 SQLITE_API void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
 SQLITE_API void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
 SQLITE_API void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
 SQLITE_API void sqlite3_result_pointer(sqlite3_context*, void*,const char*,void(*)(void*));
 SQLITE_API void sqlite3_result_zeroblob(sqlite3_context*, int n);
 SQLITE_API int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);
 
 
 /*
 ** CAPI3REF: Setting The Subtype Of An SQL Function
 ** METHOD: sqlite3_context
 **
 ** The sqlite3_result_subtype(C,T) function causes the subtype of
 ** the result from the [application-defined SQL function] with 
 ** [sqlite3_context] C to be the value T.  Only the lower 8 bits 
 ** of the subtype T are preserved in current versions of SQLite;
 ** higher order bits are discarded.
 ** The number of subtype bytes preserved by SQLite might increase
 ** in future releases of SQLite.
 */
 SQLITE_API void sqlite3_result_subtype(sqlite3_context*,unsigned int);
 
 /*
 ** CAPI3REF: Define New Collating Sequences
 ** METHOD: sqlite3
 **
 ** ^These functions add, remove, or modify a [collation] associated
 ** with the [database connection] specified as the first argument.
 **
 ** ^The name of the collation is a UTF-8 string
 ** for sqlite3_create_collation() and sqlite3_create_collation_v2()
 ** and a UTF-16 string in native byte order for sqlite3_create_collation16().
 ** ^Collation names that compare equal according to [sqlite3_strnicmp()] are
 ** considered to be the same name.
 **
 ** ^(The third argument (eTextRep) must be one of the constants:
 ** <ul>
 ** <li> [SQLITE_UTF8],
 ** <li> [SQLITE_UTF16LE],
 ** <li> [SQLITE_UTF16BE],
 ** <li> [SQLITE_UTF16], or
 ** <li> [SQLITE_UTF16_ALIGNED].
 ** </ul>)^
 ** ^The eTextRep argument determines the encoding of strings passed
 ** to the collating function callback, xCallback.
 ** ^The [SQLITE_UTF16] and [SQLITE_UTF16_ALIGNED] values for eTextRep
 ** force strings to be UTF16 with native byte order.
 ** ^The [SQLITE_UTF16_ALIGNED] value for eTextRep forces strings to begin
 ** on an even byte address.
 **
 ** ^The fourth argument, pArg, is an application data pointer that is passed
 ** through as the first argument to the collating function callback.
 **
 ** ^The fifth argument, xCallback, is a pointer to the collating function.
 ** ^Multiple collating functions can be registered using the same name but
 ** with different eTextRep parameters and SQLite will use whichever
 ** function requires the least amount of data transformation.
 ** ^If the xCallback argument is NULL then the collating function is
 ** deleted.  ^When all collating functions having the same name are deleted,
 ** that collation is no longer usable.
 **
 ** ^The collating function callback is invoked with a copy of the pArg 
 ** application data pointer and with two strings in the encoding specified
 ** by the eTextRep argument.  The collating function must return an
 ** integer that is negative, zero, or positive
 ** if the first string is less than, equal to, or greater than the second,
 ** respectively.  A collating function must always return the same answer
 ** given the same inputs.  If two or more collating functions are registered
 ** to the same collation name (using different eTextRep values) then all
 ** must give an equivalent answer when invoked with equivalent strings.
 ** The collating function must obey the following properties for all
 ** strings A, B, and C:
 **
 ** <ol>
 ** <li> If A==B then B==A.
 ** <li> If A==B and B==C then A==C.
 ** <li> If A&lt;B THEN B&gt;A.
 ** <li> If A&lt;B and B&lt;C then A&lt;C.
 ** </ol>
 **
 ** If a collating function fails any of the above constraints and that
 ** collating function is  registered and used, then the behavior of SQLite
 ** is undefined.
 **
 ** ^The sqlite3_create_collation_v2() works like sqlite3_create_collation()
 ** with the addition that the xDestroy callback is invoked on pArg when
 ** the collating function is deleted.
 ** ^Collating functions are deleted when they are overridden by later
 ** calls to the collation creation functions or when the
 ** [database connection] is closed using [sqlite3_close()].
 **
 ** ^The xDestroy callback is <u>not</u> called if the 
 ** sqlite3_create_collation_v2() function fails.  Applications that invoke
 ** sqlite3_create_collation_v2() with a non-NULL xDestroy argument should 
 ** check the return code and dispose of the application data pointer
 ** themselves rather than expecting SQLite to deal with it for them.
 ** This is different from every other SQLite interface.  The inconsistency 
 ** is unfortunate but cannot be changed without breaking backwards 
 ** compatibility.
 **
 ** See also:  [sqlite3_collation_needed()] and [sqlite3_collation_needed16()].
 */
 SQLITE_API int sqlite3_create_collation(
   sqlite3*, 
   const char *zName, 
   int eTextRep, 
   void *pArg,
   int(*xCompare)(void*,int,const void*,int,const void*)
 );
 SQLITE_API int sqlite3_create_collation_v2(
   sqlite3*, 
   const char *zName, 
   int eTextRep, 
   void *pArg,
   int(*xCompare)(void*,int,const void*,int,const void*),
   void(*xDestroy)(void*)
 );
 SQLITE_API int sqlite3_create_collation16(
   sqlite3*, 
   const void *zName,
   int eTextRep, 
   void *pArg,
   int(*xCompare)(void*,int,const void*,int,const void*)
 );
 
 /*
 ** CAPI3REF: Collation Needed Callbacks
 ** METHOD: sqlite3
 **
 ** ^To avoid having to register all collation sequences before a database
 ** can be used, a single callback function may be registered with the
 ** [database connection] to be invoked whenever an undefined collation
 ** sequence is required.
 **
 ** ^If the function is registered using the sqlite3_collation_needed() API,
 ** then it is passed the names of undefined collation sequences as strings
 ** encoded in UTF-8. ^If sqlite3_collation_needed16() is used,
 ** the names are passed as UTF-16 in machine native byte order.
 ** ^A call to either function replaces the existing collation-needed callback.
 **
 ** ^(When the callback is invoked, the first argument passed is a copy
 ** of the second argument to sqlite3_collation_needed() or
 ** sqlite3_collation_needed16().  The second argument is the database
 ** connection.  The third argument is one of [SQLITE_UTF8], [SQLITE_UTF16BE],
 ** or [SQLITE_UTF16LE], indicating the most desirable form of the collation
 ** sequence function required.  The fourth parameter is the name of the
 ** required collation sequence.)^
 **
 ** The callback function should register the desired collation using
 ** [sqlite3_create_collation()], [sqlite3_create_collation16()], or
 ** [sqlite3_create_collation_v2()].
 */
 SQLITE_API int sqlite3_collation_needed(
   sqlite3*, 
   void*, 
   void(*)(void*,sqlite3*,int eTextRep,const char*)
 );
 SQLITE_API int sqlite3_collation_needed16(
   sqlite3*, 
   void*,
   void(*)(void*,sqlite3*,int eTextRep,const void*)
 );
 
 #ifdef SQLITE_HAS_CODEC
 /*
 ** Specify the key for an encrypted database.  This routine should be
 ** called right after sqlite3_open().
 **
 ** The code to implement this API is not available in the public release
 ** of SQLite.
 */
 SQLITE_API int sqlite3_key(
   sqlite3 *db,                   /* Database to be rekeyed */
   const void *pKey, int nKey     /* The key */
 );
 SQLITE_API int sqlite3_key_v2(
   sqlite3 *db,                   /* Database to be rekeyed */
   const char *zDbName,           /* Name of the database */
   const void *pKey, int nKey     /* The key */
 );
 
 /*
 ** Change the key on an open database.  If the current database is not
 ** encrypted, this routine will encrypt it.  If pNew==0 or nNew==0, the
 ** database is decrypted.
 **
 ** The code to implement this API is not available in the public release
 ** of SQLite.
 */
 SQLITE_API int sqlite3_rekey(
   sqlite3 *db,                   /* Database to be rekeyed */
   const void *pKey, int nKey     /* The new key */
 );
 SQLITE_API int sqlite3_rekey_v2(
   sqlite3 *db,                   /* Database to be rekeyed */
   const char *zDbName,           /* Name of the database */
   const void *pKey, int nKey     /* The new key */
 );
 
 /*
 ** Specify the activation key for a SEE database.  Unless 
 ** activated, none of the SEE routines will work.
 */
 SQLITE_API void sqlite3_activate_see(
   const char *zPassPhrase        /* Activation phrase */
 );
 #endif
 
 #ifdef SQLITE_ENABLE_CEROD
 /*
 ** Specify the activation key for a CEROD database.  Unless 
 ** activated, none of the CEROD routines will work.
 */
 SQLITE_API void sqlite3_activate_cerod(
   const char *zPassPhrase        /* Activation phrase */
 );
 #endif
 
 /*
 ** CAPI3REF: Suspend Execution For A Short Time
 **
 ** The sqlite3_sleep() function causes the current thread to suspend execution
 ** for at least a number of milliseconds specified in its parameter.
 **
 ** If the operating system does not support sleep requests with
 ** millisecond time resolution, then the time will be rounded up to
 ** the nearest second. The number of milliseconds of sleep actually
 ** requested from the operating system is returned.
 **
 ** ^SQLite implements this interface by calling the xSleep()
 ** method of the default [sqlite3_vfs] object.  If the xSleep() method
 ** of the default VFS is not implemented correctly, or not implemented at
 ** all, then the behavior of sqlite3_sleep() may deviate from the description
 ** in the previous paragraphs.
 */
 SQLITE_API int sqlite3_sleep(int);
 
 /*
 ** CAPI3REF: Name Of The Folder Holding Temporary Files
 **
 ** ^(If this global variable is made to point to a string which is
 ** the name of a folder (a.k.a. directory), then all temporary files
 ** created by SQLite when using a built-in [sqlite3_vfs | VFS]
 ** will be placed in that directory.)^  ^If this variable
 ** is a NULL pointer, then SQLite performs a search for an appropriate
 ** temporary file directory.
 **
 ** Applications are strongly discouraged from using this global variable.
 ** It is required to set a temporary folder on Windows Runtime (WinRT).
 ** But for all other platforms, it is highly recommended that applications
 ** neither read nor write this variable.  This global variable is a relic
 ** that exists for backwards compatibility of legacy applications and should
 ** be avoided in new projects.
 **
 ** It is not safe to read or modify this variable in more than one
 ** thread at a time.  It is not safe to read or modify this variable
 ** if a [database connection] is being used at the same time in a separate
 ** thread.
 ** It is intended that this variable be set once
 ** as part of process initialization and before any SQLite interface
 ** routines have been called and that this variable remain unchanged
 ** thereafter.
 **
 ** ^The [temp_store_directory pragma] may modify this variable and cause
 ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
 ** the [temp_store_directory pragma] always assumes that any string
 ** that this variable points to is held in memory obtained from 
 ** [sqlite3_malloc] and the pragma may attempt to free that memory
 ** using [sqlite3_free].
 ** Hence, if this variable is modified directly, either it should be
 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
 ** or else the use of the [temp_store_directory pragma] should be avoided.
 ** Except when requested by the [temp_store_directory pragma], SQLite
 ** does not free the memory that sqlite3_temp_directory points to.  If
 ** the application wants that memory to be freed, it must do
 ** so itself, taking care to only do so after all [database connection]
 ** objects have been destroyed.
 **
 ** <b>Note to Windows Runtime users:</b>  The temporary directory must be set
 ** prior to calling [sqlite3_open] or [sqlite3_open_v2].  Otherwise, various
 ** features that require the use of temporary files may fail.  Here is an
 ** example of how to do this using C++ with the Windows Runtime:
 **
 ** <blockquote><pre>
 ** LPCWSTR zPath = Windows::Storage::ApplicationData::Current->
 ** &nbsp;     TemporaryFolder->Path->Data();
 ** char zPathBuf&#91;MAX_PATH + 1&#93;;
 ** memset(zPathBuf, 0, sizeof(zPathBuf));
 ** WideCharToMultiByte(CP_UTF8, 0, zPath, -1, zPathBuf, sizeof(zPathBuf),
 ** &nbsp;     NULL, NULL);
 ** sqlite3_temp_directory = sqlite3_mprintf("%s", zPathBuf);
 ** </pre></blockquote>
 */
 SQLITE_API SQLITE_EXTERN char *sqlite3_temp_directory;
 
 /*
 ** CAPI3REF: Name Of The Folder Holding Database Files
 **
 ** ^(If this global variable is made to point to a string which is
 ** the name of a folder (a.k.a. directory), then all database files
 ** specified with a relative pathname and created or accessed by
 ** SQLite when using a built-in windows [sqlite3_vfs | VFS] will be assumed
 ** to be relative to that directory.)^ ^If this variable is a NULL
 ** pointer, then SQLite assumes that all database files specified
 ** with a relative pathname are relative to the current directory
 ** for the process.  Only the windows VFS makes use of this global
 ** variable; it is ignored by the unix VFS.
 **
 ** Changing the value of this variable while a database connection is
 ** open can result in a corrupt database.
 **
 ** It is not safe to read or modify this variable in more than one
 ** thread at a time.  It is not safe to read or modify this variable
 ** if a [database connection] is being used at the same time in a separate
 ** thread.
 ** It is intended that this variable be set once
 ** as part of process initialization and before any SQLite interface
 ** routines have been called and that this variable remain unchanged
 ** thereafter.
 **
 ** ^The [data_store_directory pragma] may modify this variable and cause
 ** it to point to memory obtained from [sqlite3_malloc].  ^Furthermore,
 ** the [data_store_directory pragma] always assumes that any string
 ** that this variable points to is held in memory obtained from 
 ** [sqlite3_malloc] and the pragma may attempt to free that memory
 ** using [sqlite3_free].
 ** Hence, if this variable is modified directly, either it should be
 ** made NULL or made to point to memory obtained from [sqlite3_malloc]
 ** or else the use of the [data_store_directory pragma] should be avoided.
 */
 SQLITE_API SQLITE_EXTERN char *sqlite3_data_directory;
 
 /*
 ** CAPI3REF: Test For Auto-Commit Mode
 ** KEYWORDS: {autocommit mode}
 ** METHOD: sqlite3
 **
 ** ^The sqlite3_get_autocommit() interface returns non-zero or
 ** zero if the given database connection is or is not in autocommit mode,
 ** respectively.  ^Autocommit mode is on by default.
 ** ^Autocommit mode is disabled by a [BEGIN] statement.
 ** ^Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
 **
 ** If certain kinds of errors occur on a statement within a multi-statement
 ** transaction (errors including [SQLITE_FULL], [SQLITE_IOERR],
 ** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
 ** transaction might be rolled back automatically.  The only way to
 ** find out whether SQLite automatically rolled back the transaction after
 ** an error is to use this function.
 **
 ** If another thread changes the autocommit status of the database
 ** connection while this routine is running, then the return value
 ** is undefined.
 */
 SQLITE_API int sqlite3_get_autocommit(sqlite3*);
 
 /*
 ** CAPI3REF: Find The Database Handle Of A Prepared Statement
 ** METHOD: sqlite3_stmt
 **
 ** ^The sqlite3_db_handle interface returns the [database connection] handle
 ** to which a [prepared statement] belongs.  ^The [database connection]
 ** returned by sqlite3_db_handle is the same [database connection]
 ** that was the first argument
 ** to the [sqlite3_prepare_v2()] call (or its variants) that was used to
 ** create the statement in the first place.
 */
 SQLITE_API sqlite3 *sqlite3_db_handle(sqlite3_stmt*);
 
 /*
 ** CAPI3REF: Return The Filename For A Database Connection
 ** METHOD: sqlite3
 **
 ** ^The sqlite3_db_filename(D,N) interface returns a pointer to a filename
 ** associated with database N of connection D.  ^The main database file
 ** has the name "main".  If there is no attached database N on the database
 ** connection D, or if database N is a temporary or in-memory database, then
 ** a NULL pointer is returned.
 **
 ** ^The filename returned by this function is the output of the
 ** xFullPathname method of the [VFS].  ^In other words, the filename
 ** will be an absolute pathname, even if the filename used
 ** to open the database originally was a URI or relative pathname.
 */
 SQLITE_API const char *sqlite3_db_filename(sqlite3 *db, const char *zDbName);
 
 /*
 ** CAPI3REF: Determine if a database is read-only
 ** METHOD: sqlite3
 **
 ** ^The sqlite3_db_readonly(D,N) interface returns 1 if the database N
 ** of connection D is read-only, 0 if it is read/write, or -1 if N is not
 ** the name of a database on connection D.
 */
 SQLITE_API int sqlite3_db_readonly(sqlite3 *db, const char *zDbName);
 
 /*
 ** CAPI3REF: Find the next prepared statement
 ** METHOD: sqlite3
 **
 ** ^This interface returns a pointer to the next [prepared statement] after
 ** pStmt associated with the [database connection] pDb.  ^If pStmt is NULL
 ** then this interface returns a pointer to the first prepared statement
 ** associated with the database connection pDb.  ^If no prepared statement
 ** satisfies the conditions of this routine, it returns NULL.
 **
 ** The [database connection] pointer D in a call to
 ** [sqlite3_next_stmt(D,S)] must refer to an open database
 ** connection and in particular must not be a NULL pointer.
 */
 SQLITE_API sqlite3_stmt *sqlite3_next_stmt(sqlite3 *pDb, sqlite3_stmt *pStmt);
 
 /*
 ** CAPI3REF: Commit And Rollback Notification Callbacks
 ** METHOD: sqlite3
 **
 ** ^The sqlite3_commit_hook() interface registers a callback
 ** function to be invoked whenever a transaction is [COMMIT | committed].
 ** ^Any callback set by a previous call to sqlite3_commit_hook()
 ** for the same database connection is overridden.
 ** ^The sqlite3_rollback_hook() interface registers a callback
 ** function to be invoked whenever a transaction is [ROLLBACK | rolled back].
 ** ^Any callback set by a previous call to sqlite3_rollback_hook()
 ** for the same database connection is overridden.
 ** ^The pArg argument is passed through to the callback.
 ** ^If the callback on a commit hook function returns non-zero,
 ** then the commit is converted into a rollback.
 **
 ** ^The sqlite3_commit_hook(D,C,P) and sqlite3_rollback_hook(D,C,P) functions
 ** return the P argument from the previous call of the same function
 ** on the same [database connection] D, or NULL for
 ** the first call for each function on D.
 **
 ** The commit and rollback hook callbacks are not reentrant.
 ** The callback implementation must not do anything that will modify
 ** the database connection that invoked the callback.  Any actions
 ** to modify the database connection must be deferred until after the
 ** completion of the [sqlite3_step()] call that triggered the commit
 ** or rollback hook in the first place.
 ** Note that running any other SQL statements, including SELECT statements,
 ** or merely calling [sqlite3_prepare_v2()] and [sqlite3_step()] will modify
 ** the database connections for the meaning of "modify" in this paragraph.
 **
 ** ^Registering a NULL function disables the callback.
 **
 ** ^When the commit hook callback routine returns zero, the [COMMIT]
 ** operation is allowed to continue normally.  ^If the commit hook
 ** returns non-zero, then the [COMMIT] is converted into a [ROLLBACK].
 ** ^The rollback hook is invoked on a rollback that results from a commit
 ** hook returning non-zero, just as it would be with any other rollback.
 **
 ** ^For the purposes of this API, a transaction is said to have been
 ** rolled back if an explicit "ROLLBACK" statement is executed, or
 ** an error or constraint causes an implicit rollback to occur.
 ** ^The rollback callback is not invoked if a transaction is
 ** automatically rolled back because the database connection is closed.
 **
 ** See also the [sqlite3_update_hook()] interface.
 */
 SQLITE_API void *sqlite3_commit_hook(sqlite3*, int(*)(void*), void*);
 SQLITE_API void *sqlite3_rollback_hook(sqlite3*, void(*)(void *), void*);
 
 /*
 ** CAPI3REF: Data Change Notification Callbacks
 ** METHOD: sqlite3
 **
 ** ^The sqlite3_update_hook() interface registers a callback function
 ** with the [database connection] identified by the first argument
 ** to be invoked whenever a row is updated, inserted or deleted in
 ** a [rowid table].
 ** ^Any callback set by a previous call to this function
 ** for the same database connection is overridden.
 **
 ** ^The second argument is a pointer to the function to invoke when a
 ** row is updated, inserted or deleted in a rowid table.
 ** ^The first argument to the callback is a copy of the third argument
 ** to sqlite3_update_hook().
 ** ^The second callback argument is one of [SQLITE_INSERT], [SQLITE_DELETE],
 ** or [SQLITE_UPDATE], depending on the operation that caused the callback
 ** to be invoked.
 ** ^The third and fourth arguments to the callback contain pointers to the
 ** database and table name containing the affected row.
 ** ^The final callback parameter is the [rowid] of the row.
 ** ^In the case of an update, this is the [rowid] after the update takes place.
 **
 ** ^(The update hook is not invoked when internal system tables are
 ** modified (i.e. sqlite_master and sqlite_sequence).)^
 ** ^The update hook is not invoked when [WITHOUT ROWID] tables are modified.
 **
 ** ^In the current implementation, the update hook
 ** is not invoked when conflicting rows are deleted because of an
 ** [ON CONFLICT | ON CONFLICT REPLACE] clause.  ^Nor is the update hook
 ** invoked when rows are deleted using the [truncate optimization].
 ** The exceptions defined in this paragraph might change in a future
 ** release of SQLite.
 **
 ** The update hook implementation must not do anything that will modify
 ** the database connection that invoked the update hook.  Any actions
 ** to modify the database connection must be deferred until after the
 ** completion of the [sqlite3_step()] call that triggered the update hook.
 ** Note that [sqlite3_prepare_v2()] and [sqlite3_step()] both modify their
 ** database connections for the meaning of "modify" in this paragraph.
 **
 ** ^The sqlite3_update_hook(D,C,P) function
 ** returns the P argument from the previous call
 ** on the same [database connection] D, or NULL for
 ** the first call on D.
 **
 ** See also the [sqlite3_commit_hook()], [sqlite3_rollback_hook()],
 ** and [sqlite3_preupdate_hook()] interfaces.
 */
 SQLITE_API void *sqlite3_update_hook(
   sqlite3*, 
   void(*)(void *,int ,char const *,char const *,sqlite3_int64),
   void*
 );
 
 /*
 ** CAPI3REF: Enable Or Disable Shared Pager Cache
 **
 ** ^(This routine enables or disables the sharing of the database cache
 ** and schema data structures between [database connection | connections]
 ** to the same database. Sharing is enabled if the argument is true
 ** and disabled if the argument is false.)^
 **
 ** ^Cache sharing is enabled and disabled for an entire process.
 ** This is a change as of SQLite [version 3.5.0] ([dateof:3.5.0]). 
 ** In prior versions of SQLite,
 ** sharing was enabled or disabled for each thread separately.
 **
 ** ^(The cache sharing mode set by this interface effects all subsequent
 ** calls to [sqlite3_open()], [sqlite3_open_v2()], and [sqlite3_open16()].
 ** Existing database connections continue use the sharing mode
 ** that was in effect at the time they were opened.)^
 **
 ** ^(This routine returns [SQLITE_OK] if shared cache was enabled or disabled
 ** successfully.  An [error code] is returned otherwise.)^
 **
 ** ^Shared cache is disabled by default. But this might change in
 ** future releases of SQLite.  Applications that care about shared
 ** cache setting should set it explicitly.
 **
 ** Note: This method is disabled on MacOS X 10.7 and iOS version 5.0
 ** and will always return SQLITE_MISUSE. On those systems, 
 ** shared cache mode should be enabled per-database connection via 
 ** [sqlite3_open_v2()] with [SQLITE_OPEN_SHAREDCACHE].
 **
 ** This interface is threadsafe on processors where writing a
 ** 32-bit integer is atomic.
 **
 ** See Also:  [SQLite Shared-Cache Mode]
 */
 SQLITE_API int sqlite3_enable_shared_cache(int);
 
 /*
 ** CAPI3REF: Attempt To Free Heap Memory
 **
 ** ^The sqlite3_release_memory() interface attempts to free N bytes
 ** of heap memory by deallocating non-essential memory allocations
 ** held by the database library.   Memory used to cache database
 ** pages to improve performance is an example of non-essential memory.
 ** ^sqlite3_release_memory() returns the number of bytes actually freed,
 ** which might be more or less than the amount requested.
 ** ^The sqlite3_release_memory() routine is a no-op returning zero
 ** if SQLite is not compiled with [SQLITE_ENABLE_MEMORY_MANAGEMENT].
 **
 ** See also: [sqlite3_db_release_memory()]
 */
 SQLITE_API int sqlite3_release_memory(int);
 
 /*
 ** CAPI3REF: Free Memory Used By A Database Connection
 ** METHOD: sqlite3
 **
 ** ^The sqlite3_db_release_memory(D) interface attempts to free as much heap
 ** memory as possible from database connection D. Unlike the
 ** [sqlite3_release_memory()] interface, this interface is in effect even
 ** when the [SQLITE_ENABLE_MEMORY_MANAGEMENT] compile-time option is
 ** omitted.
 **
 ** See also: [sqlite3_release_memory()]
 */
 SQLITE_API int sqlite3_db_release_memory(sqlite3*);
 
 /*
 ** CAPI3REF: Impose A Limit On Heap Size
 **
 ** ^The sqlite3_soft_heap_limit64() interface sets and/or queries the
 ** soft limit on the amount of heap memory that may be allocated by SQLite.
 ** ^SQLite strives to keep heap memory utilization below the soft heap
 ** limit by reducing the number of pages held in the page cache
 ** as heap memory usages approaches the limit.
 ** ^The soft heap limit is "soft" because even though SQLite strives to stay
 ** below the limit, it will exceed the limit rather than generate
 ** an [SQLITE_NOMEM] error.  In other words, the soft heap limit 
 ** is advisory only.
 **
 ** ^The return value from sqlite3_soft_heap_limit64() is the size of
 ** the soft heap limit prior to the call, or negative in the case of an
 ** error.  ^If the argument N is negative
 ** then no change is made to the soft heap limit.  Hence, the current
 ** size of the soft heap limit can be determined by invoking
 ** sqlite3_soft_heap_limit64() with a negative argument.
 **
 ** ^If the argument N is zero then the soft heap limit is disabled.
 **
 ** ^(The soft heap limit is not enforced in the current implementation
 ** if one or more of following conditions are true:
 **
 ** <ul>
 ** <li> The soft heap limit is set to zero.
 ** <li> Memory accounting is disabled using a combination of the
 **      [sqlite3_config]([SQLITE_CONFIG_MEMSTATUS],...) start-time option and
 **      the [SQLITE_DEFAULT_MEMSTATUS] compile-time option.
 ** <li> An alternative page cache implementation is specified using
 **      [sqlite3_config]([SQLITE_CONFIG_PCACHE2],...).
 ** <li> The page cache allocates from its own memory pool supplied
 **      by [sqlite3_config]([SQLITE_CONFIG_PAGECACHE],...) rather than
 **      from the heap.
 ** </ul>)^
 **
 ** Beginning with SQLite [version 3.7.3] ([dateof:3.7.3]), 
 ** the soft heap limit is enforced
 ** regardless of whether or not the [SQLITE_ENABLE_MEMORY_MANAGEMENT]
 ** compile-time option is invoked.  With [SQLITE_ENABLE_MEMORY_MANAGEMENT],
 ** the soft heap limit is enforced on every memory allocation.  Without
 ** [SQLITE_ENABLE_MEMORY_MANAGEMENT], the soft heap limit is only enforced
 ** when memory is allocated by the page cache.  Testing suggests that because
 ** the page cache is the predominate memory user in SQLite, most
 ** applications will achieve adequate soft heap limit enforcement without
 ** the use of [SQLITE_ENABLE_MEMORY_MANAGEMENT].
 **
 ** The circumstances under which SQLite will enforce the soft heap limit may
 ** changes in future releases of SQLite.
 */
 SQLITE_API sqlite3_int64 sqlite3_soft_heap_limit64(sqlite3_int64 N);
 
 /*
 ** CAPI3REF: Deprecated Soft Heap Limit Interface
 ** DEPRECATED
 **
 ** This is a deprecated version of the [sqlite3_soft_heap_limit64()]
 ** interface.  This routine is provided for historical compatibility
 ** only.  All new applications should use the
 ** [sqlite3_soft_heap_limit64()] interface rather than this one.
 */
 SQLITE_API SQLITE_DEPRECATED void sqlite3_soft_heap_limit(int N);
 
 
 /*
 ** CAPI3REF: Extract Metadata About A Column Of A Table
 ** METHOD: sqlite3
 **
 ** ^(The sqlite3_table_column_metadata(X,D,T,C,....) routine returns
 ** information about column C of table T in database D
 ** on [database connection] X.)^  ^The sqlite3_table_column_metadata()
 ** interface returns SQLITE_OK and fills in the non-NULL pointers in
 ** the final five arguments with appropriate values if the specified
 ** column exists.  ^The sqlite3_table_column_metadata() interface returns
 ** SQLITE_ERROR and if the specified column does not exist.
 ** ^If the column-name parameter to sqlite3_table_column_metadata() is a
 ** NULL pointer, then this routine simply checks for the existence of the
 ** table and returns SQLITE_OK if the table exists and SQLITE_ERROR if it
 ** does not.  If the table name parameter T in a call to
 ** sqlite3_table_column_metadata(X,D,T,C,...) is NULL then the result is
 ** undefined behavior.
 **
 ** ^The column is identified by the second, third and fourth parameters to
 ** this function. ^(The second parameter is either the name of the database
 ** (i.e. "main", "temp", or an attached database) containing the specified
 ** table or NULL.)^ ^If it is NULL, then all attached databases are searched
 ** for the table using the same algorithm used by the database engine to
 ** resolve unqualified table references.
 **
 ** ^The third and fourth parameters to this function are the table and column
 ** name of the desired column, respectively.
 **
 ** ^Metadata is returned by writing to the memory locations passed as the 5th
 ** and subsequent parameters to this function. ^Any of these arguments may be
 ** NULL, in which case the corresponding element of metadata is omitted.
 **
 ** ^(<blockquote>
 ** <table border="1">
 ** <tr><th> Parameter <th> Output<br>Type <th>  Description
 **
 ** <tr><td> 5th <td> const char* <td> Data type
 ** <tr><td> 6th <td> const char* <td> Name of default collation sequence
 ** <tr><td> 7th <td> int         <td> True if column has a NOT NULL constraint
 ** <tr><td> 8th <td> int         <td> True if column is part of the PRIMARY KEY
 ** <tr><td> 9th <td> int         <td> True if column is [AUTOINCREMENT]
 ** </table>
 ** </blockquote>)^
 **
 ** ^The memory pointed to by the character pointers returned for the
 ** declaration type and collation sequence is valid until the next
 ** call to any SQLite API function.
 **
 ** ^If the specified table is actually a view, an [error code] is returned.
 **
 ** ^If the specified column is "rowid", "oid" or "_rowid_" and the table 
 ** is not a [WITHOUT ROWID] table and an
 ** [INTEGER PRIMARY KEY] column has been explicitly declared, then the output
 ** parameters are set for the explicitly declared column. ^(If there is no
 ** [INTEGER PRIMARY KEY] column, then the outputs
 ** for the [rowid] are set as follows:
 **
 ** <pre>
 **     data type: "INTEGER"
 **     collation sequence: "BINARY"
 **     not null: 0
 **     primary key: 1
 **     auto increment: 0
 ** </pre>)^
 **
 ** ^This function causes all database schemas to be read from disk and
 ** parsed, if that has not already been done, and returns an error if
 ** any errors are encountered while loading the schema.
 */
 SQLITE_API int sqlite3_table_column_metadata(
   sqlite3 *db,                /* Connection handle */
   const char *zDbName,        /* Database name or NULL */
   const char *zTableName,     /* Table name */
   const char *zColumnName,    /* Column name */
   char const **pzDataType,    /* OUTPUT: Declared data type */
   char const **pzCollSeq,     /* OUTPUT: Collation sequence name */
   int *pNotNull,              /* OUTPUT: True if NOT NULL constraint exists */
   int *pPrimaryKey,           /* OUTPUT: True if column part of PK */
   int *pAutoinc               /* OUTPUT: True if column is auto-increment */
 );
 
 /*
 ** CAPI3REF: Load An Extension
 ** METHOD: sqlite3
 **
 ** ^This interface loads an SQLite extension library from the named file.
 **
 ** ^The sqlite3_load_extension() interface attempts to load an
 ** [SQLite extension] library contained in the file zFile.  If
 ** the file cannot be loaded directly, attempts are made to load
 ** with various operating-system specific extensions added.
 ** So for example, if "samplelib" cannot be loaded, then names like
 ** "samplelib.so" or "samplelib.dylib" or "samplelib.dll" might
 ** be tried also.
 **
 ** ^The entry point is zProc.
 ** ^(zProc may be 0, in which case SQLite will try to come up with an
 ** entry point name on its own.  It first tries "sqlite3_extension_init".
 ** If that does not work, it constructs a name "sqlite3_X_init" where the
 ** X is consists of the lower-case equivalent of all ASCII alphabetic
 ** characters in the filename from the last "/" to the first following
 ** "." and omitting any initial "lib".)^
 ** ^The sqlite3_load_extension() interface returns
 ** [SQLITE_OK] on success and [SQLITE_ERROR] if something goes wrong.
 ** ^If an error occurs and pzErrMsg is not 0, then the
 ** [sqlite3_load_extension()] interface shall attempt to
 ** fill *pzErrMsg with error message text stored in memory
 ** obtained from [sqlite3_malloc()]. The calling function
 ** should free this memory by calling [sqlite3_free()].
 **
 ** ^Extension loading must be enabled using
 ** [sqlite3_enable_load_extension()] or
 ** [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],1,NULL)
 ** prior to calling this API,
 ** otherwise an error will be returned.
 **
 ** <b>Security warning:</b> It is recommended that the 
 ** [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method be used to enable only this
 ** interface.  The use of the [sqlite3_enable_load_extension()] interface
 ** should be avoided.  This will keep the SQL function [load_extension()]
 ** disabled and prevent SQL injections from giving attackers
 ** access to extension loading capabilities.
 **
 ** See also the [load_extension() SQL function].
 */
 SQLITE_API int sqlite3_load_extension(
   sqlite3 *db,          /* Load the extension into this database connection */
   const char *zFile,    /* Name of the shared library containing extension */
   const char *zProc,    /* Entry point.  Derived from zFile if 0 */
   char **pzErrMsg       /* Put error message here if not 0 */
 );
 
 /*
 ** CAPI3REF: Enable Or Disable Extension Loading
 ** METHOD: sqlite3
 **
 ** ^So as not to open security holes in older applications that are
 ** unprepared to deal with [extension loading], and as a means of disabling
 ** [extension loading] while evaluating user-entered SQL, the following API
 ** is provided to turn the [sqlite3_load_extension()] mechanism on and off.
 **
 ** ^Extension loading is off by default.
 ** ^Call the sqlite3_enable_load_extension() routine with onoff==1
 ** to turn extension loading on and call it with onoff==0 to turn
 ** it back off again.
 **
 ** ^This interface enables or disables both the C-API
 ** [sqlite3_load_extension()] and the SQL function [load_extension()].
 ** ^(Use [sqlite3_db_config](db,[SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION],..)
 ** to enable or disable only the C-API.)^
 **
 ** <b>Security warning:</b> It is recommended that extension loading
 ** be disabled using the [SQLITE_DBCONFIG_ENABLE_LOAD_EXTENSION] method
 ** rather than this interface, so the [load_extension()] SQL function
 ** remains disabled. This will prevent SQL injections from giving attackers
 ** access to extension loading capabilities.
 */
 SQLITE_API int sqlite3_enable_load_extension(sqlite3 *db, int onoff);
 
 /*
 ** CAPI3REF: Automatically Load Statically Linked Extensions
 **
 ** ^This interface causes the xEntryPoint() function to be invoked for
 ** each new [database connection] that is created.  The idea here is that
 ** xEntryPoint() is the entry point for a statically linked [SQLite extension]
 ** that is to be automatically loaded into all new database connections.
 **
 ** ^(Even though the function prototype shows that xEntryPoint() takes
 ** no arguments and returns void, SQLite invokes xEntryPoint() with three
 ** arguments and expects an integer result as if the signature of the
 ** entry point where as follows:
 **
 ** <blockquote><pre>
 ** &nbsp;  int xEntryPoint(
 ** &nbsp;    sqlite3 *db,
 ** &nbsp;    const char **pzErrMsg,
 ** &nbsp;    const struct sqlite3_api_routines *pThunk
 ** &nbsp;  );
 ** </pre></blockquote>)^
 **
 ** If the xEntryPoint routine encounters an error, it should make *pzErrMsg
 ** point to an appropriate error message (obtained from [sqlite3_mprintf()])
 ** and return an appropriate [error code].  ^SQLite ensures that *pzErrMsg
 ** is NULL before calling the xEntryPoint().  ^SQLite will invoke
 ** [sqlite3_free()] on *pzErrMsg after xEntryPoint() returns.  ^If any
 ** xEntryPoint() returns an error, the [sqlite3_open()], [sqlite3_open16()],
 ** or [sqlite3_open_v2()] call that provoked the xEntryPoint() will fail.
 **
 ** ^Calling sqlite3_auto_extension(X) with an entry point X that is already
 ** on the list of automatic extensions is a harmless no-op. ^No entry point
 ** will be called more than once for each database connection that is opened.
 **
 ** See also: [sqlite3_reset_auto_extension()]
 ** and [sqlite3_cancel_auto_extension()]
 */
 SQLITE_API int sqlite3_auto_extension(void(*xEntryPoint)(void));
 
 /*
 ** CAPI3REF: Cancel Automatic Extension Loading
 **
 ** ^The [sqlite3_cancel_auto_extension(X)] interface unregisters the
 ** initialization routine X that was registered using a prior call to
 ** [sqlite3_auto_extension(X)].  ^The [sqlite3_cancel_auto_extension(X)]
 ** routine returns 1 if initialization routine X was successfully 
 ** unregistered and it returns 0 if X was not on the list of initialization
 ** routines.
 */
 SQLITE_API int sqlite3_cancel_auto_extension(void(*xEntryPoint)(void));
 
 /*
 ** CAPI3REF: Reset Automatic Extension Loading
 **
 ** ^This interface disables all automatic extensions previously
 ** registered using [sqlite3_auto_extension()].
 */
 SQLITE_API void sqlite3_reset_auto_extension(void);
 
 /*
 ** The interface to the virtual-table mechanism is currently considered
 ** to be experimental.  The interface might change in incompatible ways.
 ** If this is a problem for you, do not use the interface at this time.
 **
 ** When the virtual-table mechanism stabilizes, we will declare the
 ** interface fixed, support it indefinitely, and remove this comment.
 */
 
 /*
 ** Structures used by the virtual table interface
 */
 typedef struct sqlite3_vtab sqlite3_vtab;
 typedef struct sqlite3_index_info sqlite3_index_info;
 typedef struct sqlite3_vtab_cursor sqlite3_vtab_cursor;
 typedef struct sqlite3_module sqlite3_module;
 
 /*
 ** CAPI3REF: Virtual Table Object
 ** KEYWORDS: sqlite3_module {virtual table module}
 **
 ** This structure, sometimes called a "virtual table module", 
 ** defines the implementation of a [virtual tables].  
 ** This structure consists mostly of methods for the module.
 **
 ** ^A virtual table module is created by filling in a persistent
 ** instance of this structure and passing a pointer to that instance
 ** to [sqlite3_create_module()] or [sqlite3_create_module_v2()].
 ** ^The registration remains valid until it is replaced by a different
 ** module or until the [database connection] closes.  The content
 ** of this structure must not change while it is registered with
 ** any database connection.
 */
 struct sqlite3_module {
   int iVersion;
   int (*xCreate)(sqlite3*, void *pAux,
                int argc, const char *const*argv,
                sqlite3_vtab **ppVTab, char**);
   int (*xConnect)(sqlite3*, void *pAux,
                int argc, const char *const*argv,
                sqlite3_vtab **ppVTab, char**);
   int (*xBestIndex)(sqlite3_vtab *pVTab, sqlite3_index_info*);
   int (*xDisconnect)(sqlite3_vtab *pVTab);
   int (*xDestroy)(sqlite3_vtab *pVTab);
   int (*xOpen)(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor);
   int (*xClose)(sqlite3_vtab_cursor*);
   int (*xFilter)(sqlite3_vtab_cursor*, int idxNum, const char *idxStr,
                 int argc, sqlite3_value **argv);
   int (*xNext)(sqlite3_vtab_cursor*);
   int (*xEof)(sqlite3_vtab_cursor*);
   int (*xColumn)(sqlite3_vtab_cursor*, sqlite3_context*, int);
   int (*xRowid)(sqlite3_vtab_cursor*, sqlite3_int64 *pRowid);
   int (*xUpdate)(sqlite3_vtab *, int, sqlite3_value **, sqlite3_int64 *);
   int (*xBegin)(sqlite3_vtab *pVTab);
   int (*xSync)(sqlite3_vtab *pVTab);
   int (*xCommit)(sqlite3_vtab *pVTab);
   int (*xRollback)(sqlite3_vtab *pVTab);
   int (*xFindFunction)(sqlite3_vtab *pVtab, int nArg, const char *zName,
                        void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
                        void **ppArg);
   int (*xRename)(sqlite3_vtab *pVtab, const char *zNew);
   /* The methods above are in version 1 of the sqlite_module object. Those 
   ** below are for version 2 and greater. */
   int (*xSavepoint)(sqlite3_vtab *pVTab, int);
   int (*xRelease)(sqlite3_vtab *pVTab, int);
   int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
 };
 
 /*
 ** CAPI3REF: Virtual Table Indexing Information
 ** KEYWORDS: sqlite3_index_info
 **
 ** The sqlite3_index_info structure and its substructures is used as part
 ** of the [virtual table] interface to
 ** pass information into and receive the reply from the [xBestIndex]
 ** method of a [virtual table module].  The fields under **Inputs** are the
 ** inputs to xBestIndex and are read-only.  xBestIndex inserts its
 ** results into the **Outputs** fields.
 **
 ** ^(The aConstraint[] array records WHERE clause constraints of the form:
 **
 ** <blockquote>column OP expr</blockquote>
 **
 ** where OP is =, &lt;, &lt;=, &gt;, or &gt;=.)^  ^(The particular operator is
 ** stored in aConstraint[].op using one of the
 ** [SQLITE_INDEX_CONSTRAINT_EQ | SQLITE_INDEX_CONSTRAINT_ values].)^
 ** ^(The index of the column is stored in
 ** aConstraint[].iColumn.)^  ^(aConstraint[].usable is TRUE if the
 ** expr on the right-hand side can be evaluated (and thus the constraint
 ** is usable) and false if it cannot.)^
 **
 ** ^The optimizer automatically inverts terms of the form "expr OP column"
 ** and makes other simplifications to the WHERE clause in an attempt to
 ** get as many WHERE clause terms into the form shown above as possible.
 ** ^The aConstraint[] array only reports WHERE clause terms that are
 ** relevant to the particular virtual table being queried.
 **
 ** ^Information about the ORDER BY clause is stored in aOrderBy[].
 ** ^Each term of aOrderBy records a column of the ORDER BY clause.
 **
 ** The colUsed field indicates which columns of the virtual table may be
 ** required by the current scan. Virtual table columns are numbered from
 ** zero in the order in which they appear within the CREATE TABLE statement
 ** passed to sqlite3_declare_vtab(). For the first 63 columns (columns 0-62),
 ** the corresponding bit is set within the colUsed mask if the column may be
 ** required by SQLite. If the table has at least 64 columns and any column
 ** to the right of the first 63 is required, then bit 63 of colUsed is also
 ** set. In other words, column iCol may be required if the expression
 ** (colUsed & ((sqlite3_uint64)1 << (iCol>=63 ? 63 : iCol))) evaluates to 
 ** non-zero.
 **
 ** The [xBestIndex] method must fill aConstraintUsage[] with information
 ** about what parameters to pass to xFilter.  ^If argvIndex>0 then
 ** the right-hand side of the corresponding aConstraint[] is evaluated
 ** and becomes the argvIndex-th entry in argv.  ^(If aConstraintUsage[].omit
 ** is true, then the constraint is assumed to be fully handled by the
 ** virtual table and is not checked again by SQLite.)^
 **
 ** ^The idxNum and idxPtr values are recorded and passed into the
 ** [xFilter] method.
 ** ^[sqlite3_free()] is used to free idxPtr if and only if
 ** needToFreeIdxPtr is true.
 **
 ** ^The orderByConsumed means that output from [xFilter]/[xNext] will occur in
 ** the correct order to satisfy the ORDER BY clause so that no separate
 ** sorting step is required.
 **
 ** ^The estimatedCost value is an estimate of the cost of a particular
 ** strategy. A cost of N indicates that the cost of the strategy is similar
 ** to a linear scan of an SQLite table with N rows. A cost of log(N) 
 ** indicates that the expense of the operation is similar to that of a
 ** binary search on a unique indexed field of an SQLite table with N rows.
 **
 ** ^The estimatedRows value is an estimate of the number of rows that
 ** will be returned by the strategy.
 **
 ** The xBestIndex method may optionally populate the idxFlags field with a 
 ** mask of SQLITE_INDEX_SCAN_* flags. Currently there is only one such flag -
 ** SQLITE_INDEX_SCAN_UNIQUE. If the xBestIndex method sets this flag, SQLite
 ** assumes that the strategy may visit at most one row. 
 **
 ** Additionally, if xBestIndex sets the SQLITE_INDEX_SCAN_UNIQUE flag, then
 ** SQLite also assumes that if a call to the xUpdate() method is made as
 ** part of the same statement to delete or update a virtual table row and the
 ** implementation returns SQLITE_CONSTRAINT, then there is no need to rollback
 ** any database changes. In other words, if the xUpdate() returns
 ** SQLITE_CONSTRAINT, the database contents must be exactly as they were
 ** before xUpdate was called. By contrast, if SQLITE_INDEX_SCAN_UNIQUE is not
 ** set and xUpdate returns SQLITE_CONSTRAINT, any database changes made by
 ** the xUpdate method are automatically rolled back by SQLite.
 **
 ** IMPORTANT: The estimatedRows field was added to the sqlite3_index_info
 ** structure for SQLite [version 3.8.2] ([dateof:3.8.2]). 
 ** If a virtual table extension is
 ** used with an SQLite version earlier than 3.8.2, the results of attempting 
 ** to read or write the estimatedRows field are undefined (but are likely 
 ** to included crashing the application). The estimatedRows field should
 ** therefore only be used if [sqlite3_libversion_number()] returns a
 ** value greater than or equal to 3008002. Similarly, the idxFlags field
 ** was added for [version 3.9.0] ([dateof:3.9.0]). 
 ** It may therefore only be used if
 ** sqlite3_libversion_number() returns a value greater than or equal to
 ** 3009000.
 */
 struct sqlite3_index_info {
   /* Inputs */
   int nConstraint;           /* Number of entries in aConstraint */
   struct sqlite3_index_constraint {
      int iColumn;              /* Column constrained.  -1 for ROWID */
      unsigned char op;         /* Constraint operator */
      unsigned char usable;     /* True if this constraint is usable */
      int iTermOffset;          /* Used internally - xBestIndex should ignore */
   } *aConstraint;            /* Table of WHERE clause constraints */
   int nOrderBy;              /* Number of terms in the ORDER BY clause */
   struct sqlite3_index_orderby {
      int iColumn;              /* Column number */
      unsigned char desc;       /* True for DESC.  False for ASC. */
   } *aOrderBy;               /* The ORDER BY clause */
   /* Outputs */
   struct sqlite3_index_constraint_usage {
     int argvIndex;           /* if >0, constraint is part of argv to xFilter */
     unsigned char omit;      /* Do not code a test for this constraint */
   } *aConstraintUsage;
   int idxNum;                /* Number used to identify the index */
   char *idxStr;              /* String, possibly obtained from sqlite3_malloc */
   int needToFreeIdxStr;      /* Free idxStr using sqlite3_free() if true */
   int orderByConsumed;       /* True if output is already ordered */
   double estimatedCost;           /* Estimated cost of using this index */
   /* Fields below are only available in SQLite 3.8.2 and later */
   sqlite3_int64 estimatedRows;    /* Estimated number of rows returned */
   /* Fields below are only available in SQLite 3.9.0 and later */
   int idxFlags;              /* Mask of SQLITE_INDEX_SCAN_* flags */
   /* Fields below are only available in SQLite 3.10.0 and later */
   sqlite3_uint64 colUsed;    /* Input: Mask of columns used by statement */
 };
 
 /*
 ** CAPI3REF: Virtual Table Scan Flags
 */
 #define SQLITE_INDEX_SCAN_UNIQUE      1     /* Scan visits at most 1 row */
 
 /*
 ** CAPI3REF: Virtual Table Constraint Operator Codes
 **
 ** These macros defined the allowed values for the
 ** [sqlite3_index_info].aConstraint[].op field.  Each value represents
 ** an operator that is part of a constraint term in the wHERE clause of
 ** a query that uses a [virtual table].
 */
 #define SQLITE_INDEX_CONSTRAINT_EQ         2
 #define SQLITE_INDEX_CONSTRAINT_GT         4
 #define SQLITE_INDEX_CONSTRAINT_LE         8
 #define SQLITE_INDEX_CONSTRAINT_LT        16
 #define SQLITE_INDEX_CONSTRAINT_GE        32
 #define SQLITE_INDEX_CONSTRAINT_MATCH     64
 #define SQLITE_INDEX_CONSTRAINT_LIKE      65
 #define SQLITE_INDEX_CONSTRAINT_GLOB      66
 #define SQLITE_INDEX_CONSTRAINT_REGEXP    67
 #define SQLITE_INDEX_CONSTRAINT_NE        68
 #define SQLITE_INDEX_CONSTRAINT_ISNOT     69
 #define SQLITE_INDEX_CONSTRAINT_ISNOTNULL 70
 #define SQLITE_INDEX_CONSTRAINT_ISNULL    71
 #define SQLITE_INDEX_CONSTRAINT_IS        72
 
 /*
 ** CAPI3REF: Register A Virtual Table Implementation
 ** METHOD: sqlite3
 **
 ** ^These routines are used to register a new [virtual table module] name.
 ** ^Module names must be registered before
 ** creating a new [virtual table] using the module and before using a
 ** preexisting [virtual table] for the module.
 **
 ** ^The module name is registered on the [database connection] specified
 ** by the first parameter.  ^The name of the module is given by the 
 ** second parameter.  ^The third parameter is a pointer to
 ** the implementation of the [virtual table module].   ^The fourth
 ** parameter is an arbitrary client data pointer that is passed through
 ** into the [xCreate] and [xConnect] methods of the virtual table module
 ** when a new virtual table is be being created or reinitialized.
 **
 ** ^The sqlite3_create_module_v2() interface has a fifth parameter which
 ** is a pointer to a destructor for the pClientData.  ^SQLite will
 ** invoke the destructor function (if it is not NULL) when SQLite
 ** no longer needs the pClientData pointer.  ^The destructor will also
 ** be invoked if the call to sqlite3_create_module_v2() fails.
 ** ^The sqlite3_create_module()
 ** interface is equivalent to sqlite3_create_module_v2() with a NULL
 ** destructor.
 */
 SQLITE_API int sqlite3_create_module(
   sqlite3 *db,               /* SQLite connection to register module with */
   const char *zName,         /* Name of the module */
   const sqlite3_module *p,   /* Methods for the module */
   void *pClientData          /* Client data for xCreate/xConnect */
 );
 SQLITE_API int sqlite3_create_module_v2(
   sqlite3 *db,               /* SQLite connection to register module with */
   const char *zName,         /* Name of the module */
   const sqlite3_module *p,   /* Methods for the module */
   void *pClientData,         /* Client data for xCreate/xConnect */
   void(*xDestroy)(void*)     /* Module destructor function */
 );
 
 /*
 ** CAPI3REF: Virtual Table Instance Object
 ** KEYWORDS: sqlite3_vtab
 **
 ** Every [virtual table module] implementation uses a subclass
 ** of this object to describe a particular instance
 ** of the [virtual table].  Each subclass will
 ** be tailored to the specific needs of the module implementation.
 ** The purpose of this superclass is to define certain fields that are
 ** common to all module implementations.
 **
 ** ^Virtual tables methods can set an error message by assigning a
 ** string obtained from [sqlite3_mprintf()] to zErrMsg.  The method should
 ** take care that any prior string is freed by a call to [sqlite3_free()]
 ** prior to assigning a new string to zErrMsg.  ^After the error message
 ** is delivered up to the client application, the string will be automatically
 ** freed by sqlite3_free() and the zErrMsg field will be zeroed.
 */
 struct sqlite3_vtab {
   const sqlite3_module *pModule;  /* The module for this virtual table */
   int nRef;                       /* Number of open cursors */
   char *zErrMsg;                  /* Error message from sqlite3_mprintf() */
   /* Virtual table implementations will typically add additional fields */
 };
 
 /*
 ** CAPI3REF: Virtual Table Cursor Object
 ** KEYWORDS: sqlite3_vtab_cursor {virtual table cursor}
 **
 ** Every [virtual table module] implementation uses a subclass of the
 ** following structure to describe cursors that point into the
 ** [virtual table] and are used
 ** to loop through the virtual table.  Cursors are created using the
 ** [sqlite3_module.xOpen | xOpen] method of the module and are destroyed
 ** by the [sqlite3_module.xClose | xClose] method.  Cursors are used
 ** by the [xFilter], [xNext], [xEof], [xColumn], and [xRowid] methods
 ** of the module.  Each module implementation will define
 ** the content of a cursor structure to suit its own needs.
 **
 ** This superclass exists in order to define fields of the cursor that
 ** are common to all implementations.
 */
 struct sqlite3_vtab_cursor {
   sqlite3_vtab *pVtab;      /* Virtual table of this cursor */
   /* Virtual table implementations will typically add additional fields */
 };
 
 /*
 ** CAPI3REF: Declare The Schema Of A Virtual Table
 **
 ** ^The [xCreate] and [xConnect] methods of a
 ** [virtual table module] call this interface
 ** to declare the format (the names and datatypes of the columns) of
 ** the virtual tables they implement.
 */
 SQLITE_API int sqlite3_declare_vtab(sqlite3*, const char *zSQL);
 
 /*
 ** CAPI3REF: Overload A Function For A Virtual Table
 ** METHOD: sqlite3
 **
 ** ^(Virtual tables can provide alternative implementations of functions
 ** using the [xFindFunction] method of the [virtual table module].  
 ** But global versions of those functions
 ** must exist in order to be overloaded.)^
 **
 ** ^(This API makes sure a global version of a function with a particular
 ** name and number of parameters exists.  If no such function exists
 ** before this API is called, a new function is created.)^  ^The implementation
 ** of the new function always causes an exception to be thrown.  So
 ** the new function is not good for anything by itself.  Its only
 ** purpose is to be a placeholder function that can be overloaded
 ** by a [virtual table].
 */
 SQLITE_API int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);
 
 /*
 ** The interface to the virtual-table mechanism defined above (back up
 ** to a comment remarkably similar to this one) is currently considered
 ** to be experimental.  The interface might change in incompatible ways.
 ** If this is a problem for you, do not use the interface at this time.
 **
 ** When the virtual-table mechanism stabilizes, we will declare the
 ** interface fixed, support it indefinitely, and remove this comment.
 */
 
 /*
 ** CAPI3REF: A Handle To An Open BLOB
 ** KEYWORDS: {BLOB handle} {BLOB handles}
 **
 ** An instance of this object represents an open BLOB on which
 ** [sqlite3_blob_open | incremental BLOB I/O] can be performed.
 ** ^Objects of this type are created by [sqlite3_blob_open()]
 ** and destroyed by [sqlite3_blob_close()].
 ** ^The [sqlite3_blob_read()] and [sqlite3_blob_write()] interfaces
 ** can be used to read or write small subsections of the BLOB.
 ** ^The [sqlite3_blob_bytes()] interface returns the size of the BLOB in bytes.
 */
 typedef struct sqlite3_blob sqlite3_blob;
 
 /*
 ** CAPI3REF: Open A BLOB For Incremental I/O
 ** METHOD: sqlite3
 ** CONSTRUCTOR: sqlite3_blob
 **
 ** ^(This interfaces opens a [BLOB handle | handle] to the BLOB located
 ** in row iRow, column zColumn, table zTable in database zDb;
 ** in other words, the same BLOB that would be selected by:
 **
 ** <pre>
 **     SELECT zColumn FROM zDb.zTable WHERE [rowid] = iRow;
 ** </pre>)^
 **
 ** ^(Parameter zDb is not the filename that contains the database, but 
 ** rather the symbolic name of the database. For attached databases, this is
 ** the name that appears after the AS keyword in the [ATTACH] statement.
 ** For the main database file, the database name is "main". For TEMP
 ** tables, the database name is "temp".)^
 **
 ** ^If the flags parameter is non-zero, then the BLOB is opened for read
 ** and write access. ^If the flags parameter is zero, the BLOB is opened for
 ** read-only access.
 **
 ** ^(On success, [SQLITE_OK] is returned and the new [BLOB handle] is stored
 ** in *ppBlob. Otherwise an [error code] is returned and, unless the error
 ** code is SQLITE_MISUSE, *ppBlob is set to NULL.)^ ^This means that, provided
 ** the API is not misused, it is always safe to call [sqlite3_blob_close()] 
 ** on *ppBlob after this function it returns.
 **
 ** This function fails with SQLITE_ERROR if any of the following are true:
 ** <ul>
 **   <li> ^(Database zDb does not exist)^, 
 **   <li> ^(Table zTable does not exist within database zDb)^, 
 **   <li> ^(Table zTable is a WITHOUT ROWID table)^, 
 **   <li> ^(Column zColumn does not exist)^,
 **   <li> ^(Row iRow is not present in the table)^,
 **   <li> ^(The specified column of row iRow contains a value that is not
 **         a TEXT or BLOB value)^,
 **   <li> ^(Column zColumn is part of an index, PRIMARY KEY or UNIQUE 
 **         constraint and the blob is being opened for read/write access)^,
 **   <li> ^([foreign key constraints | Foreign key constraints] are enabled, 
 **         column zColumn is part of a [child key] definition and the blob is
 **         being opened for read/write access)^.
 ** </ul>
 **
 ** ^Unless it returns SQLITE_MISUSE, this function sets the 
 ** [database connection] error code and message accessible via 
 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 
 **
 ** A BLOB referenced by sqlite3_blob_open() may be read using the
 ** [sqlite3_blob_read()] interface and modified by using
 ** [sqlite3_blob_write()].  The [BLOB handle] can be moved to a
 ** different row of the same table using the [sqlite3_blob_reopen()]
 ** interface.  However, the column, table, or database of a [BLOB handle]
 ** cannot be changed after the [BLOB handle] is opened.
 **
 ** ^(If the row that a BLOB handle points to is modified by an
 ** [UPDATE], [DELETE], or by [ON CONFLICT] side-effects
 ** then the BLOB handle is marked as "expired".
 ** This is true if any column of the row is changed, even a column
 ** other than the one the BLOB handle is open on.)^
 ** ^Calls to [sqlite3_blob_read()] and [sqlite3_blob_write()] for
 ** an expired BLOB handle fail with a return code of [SQLITE_ABORT].
 ** ^(Changes written into a BLOB prior to the BLOB expiring are not
 ** rolled back by the expiration of the BLOB.  Such changes will eventually
 ** commit if the transaction continues to completion.)^
 **
 ** ^Use the [sqlite3_blob_bytes()] interface to determine the size of
 ** the opened blob.  ^The size of a blob may not be changed by this
 ** interface.  Use the [UPDATE] SQL command to change the size of a
 ** blob.
 **
 ** ^The [sqlite3_bind_zeroblob()] and [sqlite3_result_zeroblob()] interfaces
 ** and the built-in [zeroblob] SQL function may be used to create a 
 ** zero-filled blob to read or write using the incremental-blob interface.
 **
 ** To avoid a resource leak, every open [BLOB handle] should eventually
 ** be released by a call to [sqlite3_blob_close()].
 **
 ** See also: [sqlite3_blob_close()],
 ** [sqlite3_blob_reopen()], [sqlite3_blob_read()],
 ** [sqlite3_blob_bytes()], [sqlite3_blob_write()].
 */
 SQLITE_API int sqlite3_blob_open(
   sqlite3*,
   const char *zDb,
   const char *zTable,
   const char *zColumn,
   sqlite3_int64 iRow,
   int flags,
   sqlite3_blob **ppBlob
 );
 
 /*
 ** CAPI3REF: Move a BLOB Handle to a New Row
 ** METHOD: sqlite3_blob
 **
 ** ^This function is used to move an existing [BLOB handle] so that it points
 ** to a different row of the same database table. ^The new row is identified
 ** by the rowid value passed as the second argument. Only the row can be
 ** changed. ^The database, table and column on which the blob handle is open
 ** remain the same. Moving an existing [BLOB handle] to a new row is
 ** faster than closing the existing handle and opening a new one.
 **
 ** ^(The new row must meet the same criteria as for [sqlite3_blob_open()] -
 ** it must exist and there must be either a blob or text value stored in
 ** the nominated column.)^ ^If the new row is not present in the table, or if
 ** it does not contain a blob or text value, or if another error occurs, an
 ** SQLite error code is returned and the blob handle is considered aborted.
 ** ^All subsequent calls to [sqlite3_blob_read()], [sqlite3_blob_write()] or
 ** [sqlite3_blob_reopen()] on an aborted blob handle immediately return
 ** SQLITE_ABORT. ^Calling [sqlite3_blob_bytes()] on an aborted blob handle
 ** always returns zero.
 **
 ** ^This function sets the database handle error code and message.
 */
 SQLITE_API int sqlite3_blob_reopen(sqlite3_blob *, sqlite3_int64);
 
 /*
 ** CAPI3REF: Close A BLOB Handle
 ** DESTRUCTOR: sqlite3_blob
 **
 ** ^This function closes an open [BLOB handle]. ^(The BLOB handle is closed
 ** unconditionally.  Even if this routine returns an error code, the 
 ** handle is still closed.)^
 **
 ** ^If the blob handle being closed was opened for read-write access, and if
 ** the database is in auto-commit mode and there are no other open read-write
 ** blob handles or active write statements, the current transaction is
 ** committed. ^If an error occurs while committing the transaction, an error
 ** code is returned and the transaction rolled back.
 **
 ** Calling this function with an argument that is not a NULL pointer or an
 ** open blob handle results in undefined behaviour. ^Calling this routine 
 ** with a null pointer (such as would be returned by a failed call to 
 ** [sqlite3_blob_open()]) is a harmless no-op. ^Otherwise, if this function
 ** is passed a valid open blob handle, the values returned by the 
 ** sqlite3_errcode() and sqlite3_errmsg() functions are set before returning.
 */
 SQLITE_API int sqlite3_blob_close(sqlite3_blob *);
 
 /*
 ** CAPI3REF: Return The Size Of An Open BLOB
 ** METHOD: sqlite3_blob
 **
 ** ^Returns the size in bytes of the BLOB accessible via the 
 ** successfully opened [BLOB handle] in its only argument.  ^The
 ** incremental blob I/O routines can only read or overwriting existing
 ** blob content; they cannot change the size of a blob.
 **
 ** This routine only works on a [BLOB handle] which has been created
 ** by a prior successful call to [sqlite3_blob_open()] and which has not
 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
 ** to this routine results in undefined and probably undesirable behavior.
 */
 SQLITE_API int sqlite3_blob_bytes(sqlite3_blob *);
 
 /*
 ** CAPI3REF: Read Data From A BLOB Incrementally
 ** METHOD: sqlite3_blob
 **
 ** ^(This function is used to read data from an open [BLOB handle] into a
 ** caller-supplied buffer. N bytes of data are copied into buffer Z
 ** from the open BLOB, starting at offset iOffset.)^
 **
 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
 ** [SQLITE_ERROR] is returned and no data is read.  ^If N or iOffset is
 ** less than zero, [SQLITE_ERROR] is returned and no data is read.
 ** ^The size of the blob (and hence the maximum value of N+iOffset)
 ** can be determined using the [sqlite3_blob_bytes()] interface.
 **
 ** ^An attempt to read from an expired [BLOB handle] fails with an
 ** error code of [SQLITE_ABORT].
 **
 ** ^(On success, sqlite3_blob_read() returns SQLITE_OK.
 ** Otherwise, an [error code] or an [extended error code] is returned.)^
 **
 ** This routine only works on a [BLOB handle] which has been created
 ** by a prior successful call to [sqlite3_blob_open()] and which has not
 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
 ** to this routine results in undefined and probably undesirable behavior.
 **
 ** See also: [sqlite3_blob_write()].
 */
 SQLITE_API int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);
 
 /*
 ** CAPI3REF: Write Data Into A BLOB Incrementally
 ** METHOD: sqlite3_blob
 **
 ** ^(This function is used to write data into an open [BLOB handle] from a
 ** caller-supplied buffer. N bytes of data are copied from the buffer Z
 ** into the open BLOB, starting at offset iOffset.)^
 **
 ** ^(On success, sqlite3_blob_write() returns SQLITE_OK.
 ** Otherwise, an  [error code] or an [extended error code] is returned.)^
 ** ^Unless SQLITE_MISUSE is returned, this function sets the 
 ** [database connection] error code and message accessible via 
 ** [sqlite3_errcode()] and [sqlite3_errmsg()] and related functions. 
 **
 ** ^If the [BLOB handle] passed as the first argument was not opened for
 ** writing (the flags parameter to [sqlite3_blob_open()] was zero),
 ** this function returns [SQLITE_READONLY].
 **
 ** This function may only modify the contents of the BLOB; it is
 ** not possible to increase the size of a BLOB using this API.
 ** ^If offset iOffset is less than N bytes from the end of the BLOB,
 ** [SQLITE_ERROR] is returned and no data is written. The size of the 
 ** BLOB (and hence the maximum value of N+iOffset) can be determined 
 ** using the [sqlite3_blob_bytes()] interface. ^If N or iOffset are less 
 ** than zero [SQLITE_ERROR] is returned and no data is written.
 **
 ** ^An attempt to write to an expired [BLOB handle] fails with an
 ** error code of [SQLITE_ABORT].  ^Writes to the BLOB that occurred
 ** before the [BLOB handle] expired are not rolled back by the
 ** expiration of the handle, though of course those changes might
 ** have been overwritten by the statement that expired the BLOB handle
 ** or by other independent statements.
 **
 ** This routine only works on a [BLOB handle] which has been created
 ** by a prior successful call to [sqlite3_blob_open()] and which has not
 ** been closed by [sqlite3_blob_close()].  Passing any other pointer in
 ** to this routine results in undefined and probably undesirable behavior.
 **
 ** See also: [sqlite3_blob_read()].
 */
 SQLITE_API int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);
 
 /*
 ** CAPI3REF: Virtual File System Objects
 **
 ** A virtual filesystem (VFS) is an [sqlite3_vfs] object
 ** that SQLite uses to interact
 ** with the underlying operating system.  Most SQLite builds come with a
 ** single default VFS that is appropriate for the host computer.
 ** New VFSes can be registered and existing VFSes can be unregistered.
 ** The following interfaces are provided.
 **
 ** ^The sqlite3_vfs_find() interface returns a pointer to a VFS given its name.
 ** ^Names are case sensitive.
 ** ^Names are zero-terminated UTF-8 strings.
 ** ^If there is no match, a NULL pointer is returned.
 ** ^If zVfsName is NULL then the default VFS is returned.
 **
 ** ^New VFSes are registered with sqlite3_vfs_register().
 ** ^Each new VFS becomes the default VFS if the makeDflt flag is set.
 ** ^The same VFS can be registered multiple times without injury.
 ** ^To make an existing VFS into the default VFS, register it again
 ** with the makeDflt flag set.  If two different VFSes with the
 ** same name are registered, the behavior is undefined.  If a
 ** VFS is registered with a name that is NULL or an empty string,
 ** then the behavior is undefined.
 **
 ** ^Unregister a VFS with the sqlite3_vfs_unregister() interface.
 ** ^(If the default VFS is unregistered, another VFS is chosen as
 ** the default.  The choice for the new VFS is arbitrary.)^
 */
 SQLITE_API sqlite3_vfs *sqlite3_vfs_find(const char *zVfsName);
 SQLITE_API int sqlite3_vfs_register(sqlite3_vfs*, int makeDflt);
 SQLITE_API int sqlite3_vfs_unregister(sqlite3_vfs*);
 
 /*
 ** CAPI3REF: Mutexes
 **
 ** The SQLite core uses these routines for thread
 ** synchronization. Though they are intended for internal
 ** use by SQLite, code that links against SQLite is
 ** permitted to use any of these routines.
 **
 ** The SQLite source code contains multiple implementations
 ** of these mutex routines.  An appropriate implementation
 ** is selected automatically at compile-time.  The following
 ** implementations are available in the SQLite core:
 **
 ** <ul>
 ** <li>   SQLITE_MUTEX_PTHREADS
 ** <li>   SQLITE_MUTEX_W32
 ** <li>   SQLITE_MUTEX_NOOP
 ** </ul>
 **
 ** The SQLITE_MUTEX_NOOP implementation is a set of routines
 ** that does no real locking and is appropriate for use in
 ** a single-threaded application.  The SQLITE_MUTEX_PTHREADS and
 ** SQLITE_MUTEX_W32 implementations are appropriate for use on Unix
 ** and Windows.
 **
 ** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
 ** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
 ** implementation is included with the library. In this case the
 ** application must supply a custom mutex implementation using the
 ** [SQLITE_CONFIG_MUTEX] option of the sqlite3_config() function
 ** before calling sqlite3_initialize() or any other public sqlite3_
 ** function that calls sqlite3_initialize().
 **
 ** ^The sqlite3_mutex_alloc() routine allocates a new
 ** mutex and returns a pointer to it. ^The sqlite3_mutex_alloc()
 ** routine returns NULL if it is unable to allocate the requested
 ** mutex.  The argument to sqlite3_mutex_alloc() must one of these
 ** integer constants:
 **
 ** <ul>
 ** <li>  SQLITE_MUTEX_FAST
 ** <li>  SQLITE_MUTEX_RECURSIVE
 ** <li>  SQLITE_MUTEX_STATIC_MASTER
 ** <li>  SQLITE_MUTEX_STATIC_MEM
 ** <li>  SQLITE_MUTEX_STATIC_OPEN
 ** <li>  SQLITE_MUTEX_STATIC_PRNG
 ** <li>  SQLITE_MUTEX_STATIC_LRU
 ** <li>  SQLITE_MUTEX_STATIC_PMEM
 ** <li>  SQLITE_MUTEX_STATIC_APP1
 ** <li>  SQLITE_MUTEX_STATIC_APP2
 ** <li>  SQLITE_MUTEX_STATIC_APP3
 ** <li>  SQLITE_MUTEX_STATIC_VFS1
 ** <li>  SQLITE_MUTEX_STATIC_VFS2
 ** <li>  SQLITE_MUTEX_STATIC_VFS3
 ** </ul>
 **
 ** ^The first two constants (SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE)
 ** cause sqlite3_mutex_alloc() to create
 ** a new mutex.  ^The new mutex is recursive when SQLITE_MUTEX_RECURSIVE
 ** is used but not necessarily so when SQLITE_MUTEX_FAST is used.
 ** The mutex implementation does not need to make a distinction
 ** between SQLITE_MUTEX_RECURSIVE and SQLITE_MUTEX_FAST if it does
 ** not want to.  SQLite will only request a recursive mutex in
 ** cases where it really needs one.  If a faster non-recursive mutex
 ** implementation is available on the host platform, the mutex subsystem
 ** might return such a mutex in response to SQLITE_MUTEX_FAST.
 **
 ** ^The other allowed parameters to sqlite3_mutex_alloc() (anything other
 ** than SQLITE_MUTEX_FAST and SQLITE_MUTEX_RECURSIVE) each return
 ** a pointer to a static preexisting mutex.  ^Nine static mutexes are
 ** used by the current version of SQLite.  Future versions of SQLite
 ** may add additional static mutexes.  Static mutexes are for internal
 ** use by SQLite only.  Applications that use SQLite mutexes should
 ** use only the dynamic mutexes returned by SQLITE_MUTEX_FAST or
 ** SQLITE_MUTEX_RECURSIVE.
 **
 ** ^Note that if one of the dynamic mutex parameters (SQLITE_MUTEX_FAST
 ** or SQLITE_MUTEX_RECURSIVE) is used then sqlite3_mutex_alloc()
 ** returns a different mutex on every call.  ^For the static
 ** mutex types, the same mutex is returned on every call that has
 ** the same type number.
 **
 ** ^The sqlite3_mutex_free() routine deallocates a previously
 ** allocated dynamic mutex.  Attempting to deallocate a static
 ** mutex results in undefined behavior.
 **
 ** ^The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
 ** to enter a mutex.  ^If another thread is already within the mutex,
 ** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
 ** SQLITE_BUSY.  ^The sqlite3_mutex_try() interface returns [SQLITE_OK]
 ** upon successful entry.  ^(Mutexes created using
 ** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
 ** In such cases, the
 ** mutex must be exited an equal number of times before another thread
 ** can enter.)^  If the same thread tries to enter any mutex other
 ** than an SQLITE_MUTEX_RECURSIVE more than once, the behavior is undefined.
 **
 ** ^(Some systems (for example, Windows 95) do not support the operation
 ** implemented by sqlite3_mutex_try().  On those systems, sqlite3_mutex_try()
 ** will always return SQLITE_BUSY. The SQLite core only ever uses
 ** sqlite3_mutex_try() as an optimization so this is acceptable 
 ** behavior.)^
 **
 ** ^The sqlite3_mutex_leave() routine exits a mutex that was
 ** previously entered by the same thread.   The behavior
 ** is undefined if the mutex is not currently entered by the
 ** calling thread or is not currently allocated.
 **
 ** ^If the argument to sqlite3_mutex_enter(), sqlite3_mutex_try(), or
 ** sqlite3_mutex_leave() is a NULL pointer, then all three routines
 ** behave as no-ops.
 **
 ** See also: [sqlite3_mutex_held()] and [sqlite3_mutex_notheld()].
 */
 SQLITE_API sqlite3_mutex *sqlite3_mutex_alloc(int);
 SQLITE_API void sqlite3_mutex_free(sqlite3_mutex*);
 SQLITE_API void sqlite3_mutex_enter(sqlite3_mutex*);
 SQLITE_API int sqlite3_mutex_try(sqlite3_mutex*);
 SQLITE_API void sqlite3_mutex_leave(sqlite3_mutex*);
 
 /*
 ** CAPI3REF: Mutex Methods Object
 **
 ** An instance of this structure defines the low-level routines
 ** used to allocate and use mutexes.
 **
 ** Usually, the default mutex implementations provided by SQLite are
 ** sufficient, however the application has the option of substituting a custom
 ** implementation for specialized deployments or systems for which SQLite
 ** does not provide a suitable implementation. In this case, the application
 ** creates and populates an instance of this structure to pass
 ** to sqlite3_config() along with the [SQLITE_CONFIG_MUTEX] option.
 ** Additionally, an instance of this structure can be used as an
 ** output variable when querying the system for the current mutex
 ** implementation, using the [SQLITE_CONFIG_GETMUTEX] option.
 **
 ** ^The xMutexInit method defined by this structure is invoked as
 ** part of system initialization by the sqlite3_initialize() function.
 ** ^The xMutexInit routine is called by SQLite exactly once for each
 ** effective call to [sqlite3_initialize()].
 **
 ** ^The xMutexEnd method defined by this structure is invoked as
 ** part of system shutdown by the sqlite3_shutdown() function. The
 ** implementation of this method is expected to release all outstanding
 ** resources obtained by the mutex methods implementation, especially
 ** those obtained by the xMutexInit method.  ^The xMutexEnd()
 ** interface is invoked exactly once for each call to [sqlite3_shutdown()].
 **
 ** ^(The remaining seven methods defined by this structure (xMutexAlloc,
 ** xMutexFree, xMutexEnter, xMutexTry, xMutexLeave, xMutexHeld and
 ** xMutexNotheld) implement the following interfaces (respectively):
 **
 ** <ul>
 **   <li>  [sqlite3_mutex_alloc()] </li>
 **   <li>  [sqlite3_mutex_free()] </li>
 **   <li>  [sqlite3_mutex_enter()] </li>
 **   <li>  [sqlite3_mutex_try()] </li>
 **   <li>  [sqlite3_mutex_leave()] </li>
 **   <li>  [sqlite3_mutex_held()] </li>
 **   <li>  [sqlite3_mutex_notheld()] </li>
 ** </ul>)^
 **
 ** The only difference is that the public sqlite3_XXX functions enumerated
 ** above silently ignore any invocations that pass a NULL pointer instead
 ** of a valid mutex handle. The implementations of the methods defined
 ** by this structure are not required to handle this case, the results
 ** of passing a NULL pointer instead of a valid mutex handle are undefined
 ** (i.e. it is acceptable to provide an implementation that segfaults if
 ** it is passed a NULL pointer).
 **
 ** The xMutexInit() method must be threadsafe.  It must be harmless to
 ** invoke xMutexInit() multiple times within the same process and without
 ** intervening calls to xMutexEnd().  Second and subsequent calls to
 ** xMutexInit() must be no-ops.
 **
 ** xMutexInit() must not use SQLite memory allocation ([sqlite3_malloc()]
 ** and its associates).  Similarly, xMutexAlloc() must not use SQLite memory
 ** allocation for a static mutex.  ^However xMutexAlloc() may use SQLite
 ** memory allocation for a fast or recursive mutex.
 **
 ** ^SQLite will invoke the xMutexEnd() method when [sqlite3_shutdown()] is
 ** called, but only if the prior call to xMutexInit returned SQLITE_OK.
 ** If xMutexInit fails in any way, it is expected to clean up after itself
 ** prior to returning.
 */
 typedef struct sqlite3_mutex_methods sqlite3_mutex_methods;
 struct sqlite3_mutex_methods {
   int (*xMutexInit)(void);
   int (*xMutexEnd)(void);
   sqlite3_mutex *(*xMutexAlloc)(int);
   void (*xMutexFree)(sqlite3_mutex *);
   void (*xMutexEnter)(sqlite3_mutex *);
   int (*xMutexTry)(sqlite3_mutex *);
   void (*xMutexLeave)(sqlite3_mutex *);
   int (*xMutexHeld)(sqlite3_mutex *);
   int (*xMutexNotheld)(sqlite3_mutex *);
 };
 
 /*
 ** CAPI3REF: Mutex Verification Routines
 **
 ** The sqlite3_mutex_held() and sqlite3_mutex_notheld() routines
 ** are intended for use inside assert() statements.  The SQLite core
 ** never uses these routines except inside an assert() and applications
 ** are advised to follow the lead of the core.  The SQLite core only
 ** provides implementations for these routines when it is compiled
 ** with the SQLITE_DEBUG flag.  External mutex implementations
 ** are only required to provide these routines if SQLITE_DEBUG is
 ** defined and if NDEBUG is not defined.
 **
 ** These routines should return true if the mutex in their argument
 ** is held or not held, respectively, by the calling thread.
 **
 ** The implementation is not required to provide versions of these
 ** routines that actually work. If the implementation does not provide working
 ** versions of these routines, it should at least provide stubs that always
 ** return true so that one does not get spurious assertion failures.
 **
 ** If the argument to sqlite3_mutex_held() is a NULL pointer then
 ** the routine should return 1.   This seems counter-intuitive since
 ** clearly the mutex cannot be held if it does not exist.  But
 ** the reason the mutex does not exist is because the build is not
 ** using mutexes.  And we do not want the assert() containing the
 ** call to sqlite3_mutex_held() to fail, so a non-zero return is
 ** the appropriate thing to do.  The sqlite3_mutex_notheld()
 ** interface should also return 1 when given a NULL pointer.
 */
 #ifndef NDEBUG
 SQLITE_API int sqlite3_mutex_held(sqlite3_mutex*);
 SQLITE_API int sqlite3_mutex_notheld(sqlite3_mutex*);
 #endif
 
 /*
 ** CAPI3REF: Mutex Types
 **
 ** The [sqlite3_mutex_alloc()] interface takes a single argument
 ** which is one of these integer constants.
 **
 ** The set of static mutexes may change from one SQLite release to the
 ** next.  Applications that override the built-in mutex logic must be
 ** prepared to accommodate additional static mutexes.
 */
 #define SQLITE_MUTEX_FAST             0
 #define SQLITE_MUTEX_RECURSIVE        1
 #define SQLITE_MUTEX_STATIC_MASTER    2
 #define SQLITE_MUTEX_STATIC_MEM       3  /* sqlite3_malloc() */
 #define SQLITE_MUTEX_STATIC_MEM2      4  /* NOT USED */
 #define SQLITE_MUTEX_STATIC_OPEN      4  /* sqlite3BtreeOpen() */
 #define SQLITE_MUTEX_STATIC_PRNG      5  /* sqlite3_randomness() */
 #define SQLITE_MUTEX_STATIC_LRU       6  /* lru page list */
 #define SQLITE_MUTEX_STATIC_LRU2      7  /* NOT USED */
 #define SQLITE_MUTEX_STATIC_PMEM      7  /* sqlite3PageMalloc() */
 #define SQLITE_MUTEX_STATIC_APP1      8  /* For use by application */
 #define SQLITE_MUTEX_STATIC_APP2      9  /* For use by application */
 #define SQLITE_MUTEX_STATIC_APP3     10  /* For use by application */
 #define SQLITE_MUTEX_STATIC_VFS1     11  /* For use by built-in VFS */
 #define SQLITE_MUTEX_STATIC_VFS2     12  /* For use by extension VFS */
 #define SQLITE_MUTEX_STATIC_VFS3     13  /* For use by application VFS */
 
 /*
 ** CAPI3REF: Retrieve the mutex for a database connection
 ** METHOD: sqlite3
 **
 ** ^This interface returns a pointer the [sqlite3_mutex] object that 
 ** serializes access to the [database connection] given in the argument
 ** when the [threading mode] is Serialized.
 ** ^If the [threading mode] is Single-thread or Multi-thread then this
 ** routine returns a NULL pointer.
 */
 SQLITE_API sqlite3_mutex *sqlite3_db_mutex(sqlite3*);
 
 /*
 ** CAPI3REF: Low-Level Control Of Database Files
 ** METHOD: sqlite3
 **
 ** ^The [sqlite3_file_control()] interface makes a direct call to the
 ** xFileControl method for the [sqlite3_io_methods] object associated
 ** with a particular database identified by the second argument. ^The
 ** name of the database is "main" for the main database or "temp" for the
 ** TEMP database, or the name that appears after the AS keyword for
 ** databases that are added using the [ATTACH] SQL command.
 ** ^A NULL pointer can be used in place of "main" to refer to the
 ** main database file.
 ** ^The third and fourth parameters to this routine
 ** are passed directly through to the second and third parameters of
 ** the xFileControl method.  ^The return value of the xFileControl
 ** method becomes the return value of this routine.
 **
 ** ^The [SQLITE_FCNTL_FILE_POINTER] value for the op parameter causes
 ** a pointer to the underlying [sqlite3_file] object to be written into
 ** the space pointed to by the 4th parameter.  ^The [SQLITE_FCNTL_FILE_POINTER]
 ** case is a short-circuit path which does not actually invoke the
 ** underlying sqlite3_io_methods.xFileControl method.
 **
 ** ^If the second parameter (zDbName) does not match the name of any
 ** open database file, then SQLITE_ERROR is returned.  ^This error
 ** code is not remembered and will not be recalled by [sqlite3_errcode()]
 ** or [sqlite3_errmsg()].  The underlying xFileControl method might
 ** also return SQLITE_ERROR.  There is no way to distinguish between
 ** an incorrect zDbName and an SQLITE_ERROR return from the underlying
 ** xFileControl method.
 **
 ** See also: [file control opcodes]
 */
 SQLITE_API int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);
 
 /*
 ** CAPI3REF: Testing Interface
 **
 ** ^The sqlite3_test_control() interface is used to read out internal
 ** state of SQLite and to inject faults into SQLite for testing
 ** purposes.  ^The first parameter is an operation code that determines
 ** the number, meaning, and operation of all subsequent parameters.
 **
 ** This interface is not for use by applications.  It exists solely
 ** for verifying the correct operation of the SQLite library.  Depending
 ** on how the SQLite library is compiled, this interface might not exist.
 **
 ** The details of the operation codes, their meanings, the parameters
 ** they take, and what they do are all subject to change without notice.
 ** Unlike most of the SQLite API, this function is not guaranteed to
 ** operate consistently from one release to the next.
 */
 SQLITE_API int sqlite3_test_control(int op, ...);
 
 /*
 ** CAPI3REF: Testing Interface Operation Codes
 **
 ** These constants are the valid operation code parameters used
 ** as the first argument to [sqlite3_test_control()].
 **
 ** These parameters and their meanings are subject to change
 ** without notice.  These values are for testing purposes only.
 ** Applications should not use any of these parameters or the
 ** [sqlite3_test_control()] interface.
 */
 #define SQLITE_TESTCTRL_FIRST                    5
 #define SQLITE_TESTCTRL_PRNG_SAVE                5
 #define SQLITE_TESTCTRL_PRNG_RESTORE             6
 #define SQLITE_TESTCTRL_PRNG_RESET               7
 #define SQLITE_TESTCTRL_BITVEC_TEST              8
 #define SQLITE_TESTCTRL_FAULT_INSTALL            9
 #define SQLITE_TESTCTRL_BENIGN_MALLOC_HOOKS     10
 #define SQLITE_TESTCTRL_PENDING_BYTE            11
 #define SQLITE_TESTCTRL_ASSERT                  12
 #define SQLITE_TESTCTRL_ALWAYS                  13
 #define SQLITE_TESTCTRL_RESERVE                 14
 #define SQLITE_TESTCTRL_OPTIMIZATIONS           15
 #define SQLITE_TESTCTRL_ISKEYWORD               16
 #define SQLITE_TESTCTRL_SCRATCHMALLOC           17  /* NOT USED */
 #define SQLITE_TESTCTRL_LOCALTIME_FAULT         18
 #define SQLITE_TESTCTRL_EXPLAIN_STMT            19  /* NOT USED */
 #define SQLITE_TESTCTRL_ONCE_RESET_THRESHOLD    19
 #define SQLITE_TESTCTRL_NEVER_CORRUPT           20
 #define SQLITE_TESTCTRL_VDBE_COVERAGE           21
 #define SQLITE_TESTCTRL_BYTEORDER               22
 #define SQLITE_TESTCTRL_ISINIT                  23
 #define SQLITE_TESTCTRL_SORTER_MMAP             24
 #define SQLITE_TESTCTRL_IMPOSTER                25
 #define SQLITE_TESTCTRL_PARSER_COVERAGE         26
 #define SQLITE_TESTCTRL_LAST                    26  /* Largest TESTCTRL */
 
 /*
 ** CAPI3REF: SQLite Runtime Status
 **
 ** ^These interfaces are used to retrieve runtime status information
 ** about the performance of SQLite, and optionally to reset various
 ** highwater marks.  ^The first argument is an integer code for
 ** the specific parameter to measure.  ^(Recognized integer codes
 ** are of the form [status parameters | SQLITE_STATUS_...].)^
 ** ^The current value of the parameter is returned into *pCurrent.
 ** ^The highest recorded value is returned in *pHighwater.  ^If the
 ** resetFlag is true, then the highest record value is reset after
 ** *pHighwater is written.  ^(Some parameters do not record the highest
 ** value.  For those parameters
 ** nothing is written into *pHighwater and the resetFlag is ignored.)^
 ** ^(Other parameters record only the highwater mark and not the current
 ** value.  For these latter parameters nothing is written into *pCurrent.)^
 **
 ** ^The sqlite3_status() and sqlite3_status64() routines return
 ** SQLITE_OK on success and a non-zero [error code] on failure.
 **
 ** If either the current value or the highwater mark is too large to
 ** be represented by a 32-bit integer, then the values returned by
 ** sqlite3_status() are undefined.
 **
 ** See also: [sqlite3_db_status()]
 */
 SQLITE_API int sqlite3_status(int op, int *pCurrent, int *pHighwater, int resetFlag);
 SQLITE_API int sqlite3_status64(
   int op,
   sqlite3_int64 *pCurrent,
   sqlite3_int64 *pHighwater,
   int resetFlag
 );
 
 
 /*
 ** CAPI3REF: Status Parameters
 ** KEYWORDS: {status parameters}
 **
 ** These integer constants designate various run-time status parameters
 ** that can be returned by [sqlite3_status()].
 **
 ** <dl>
 ** [[SQLITE_STATUS_MEMORY_USED]] ^(<dt>SQLITE_STATUS_MEMORY_USED</dt>
 ** <dd>This parameter is the current amount of memory checked out
 ** using [sqlite3_malloc()], either directly or indirectly.  The
 ** figure includes calls made to [sqlite3_malloc()] by the application
 ** and internal memory usage by the SQLite library.  Auxiliary page-cache
 ** memory controlled by [SQLITE_CONFIG_PAGECACHE] is not included in
 ** this parameter.  The amount returned is the sum of the allocation
 ** sizes as reported by the xSize method in [sqlite3_mem_methods].</dd>)^
 **
 ** [[SQLITE_STATUS_MALLOC_SIZE]] ^(<dt>SQLITE_STATUS_MALLOC_SIZE</dt>
 ** <dd>This parameter records the largest memory allocation request
 ** handed to [sqlite3_malloc()] or [sqlite3_realloc()] (or their
 ** internal equivalents).  Only the value returned in the
 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
 ** The value written into the *pCurrent parameter is undefined.</dd>)^
 **
 ** [[SQLITE_STATUS_MALLOC_COUNT]] ^(<dt>SQLITE_STATUS_MALLOC_COUNT</dt>
 ** <dd>This parameter records the number of separate memory allocations
 ** currently checked out.</dd>)^
 **
 ** [[SQLITE_STATUS_PAGECACHE_USED]] ^(<dt>SQLITE_STATUS_PAGECACHE_USED</dt>
 ** <dd>This parameter returns the number of pages used out of the
 ** [pagecache memory allocator] that was configured using 
 ** [SQLITE_CONFIG_PAGECACHE].  The
 ** value returned is in pages, not in bytes.</dd>)^
 **
 ** [[SQLITE_STATUS_PAGECACHE_OVERFLOW]] 
 ** ^(<dt>SQLITE_STATUS_PAGECACHE_OVERFLOW</dt>
 ** <dd>This parameter returns the number of bytes of page cache
 ** allocation which could not be satisfied by the [SQLITE_CONFIG_PAGECACHE]
 ** buffer and where forced to overflow to [sqlite3_malloc()].  The
 ** returned value includes allocations that overflowed because they
 ** where too large (they were larger than the "sz" parameter to
 ** [SQLITE_CONFIG_PAGECACHE]) and allocations that overflowed because
 ** no space was left in the page cache.</dd>)^
 **
 ** [[SQLITE_STATUS_PAGECACHE_SIZE]] ^(<dt>SQLITE_STATUS_PAGECACHE_SIZE</dt>
 ** <dd>This parameter records the largest memory allocation request
 ** handed to [pagecache memory allocator].  Only the value returned in the
 ** *pHighwater parameter to [sqlite3_status()] is of interest.  
 ** The value written into the *pCurrent parameter is undefined.</dd>)^
 **
 ** [[SQLITE_STATUS_SCRATCH_USED]] <dt>SQLITE_STATUS_SCRATCH_USED</dt>
 ** <dd>No longer used.</dd>
 **
 ** [[SQLITE_STATUS_SCRATCH_OVERFLOW]] ^(<dt>SQLITE_STATUS_SCRATCH_OVERFLOW</dt>
 ** <dd>No longer used.</dd>
 **
 ** [[SQLITE_STATUS_SCRATCH_SIZE]] <dt>SQLITE_STATUS_SCRATCH_SIZE</dt>
 ** <dd>No longer used.</dd>
 **
 ** [[SQLITE_STATUS_PARSER_STACK]] ^(<dt>SQLITE_STATUS_PARSER_STACK</dt>
 ** <dd>The *pHighwater parameter records the deepest parser stack. 
 ** The *pCurrent value is undefined.  The *pHighwater value is only
 ** meaningful if SQLite is compiled with [YYTRACKMAXSTACKDEPTH].</dd>)^
 ** </dl>
 **
 ** New status parameters may be added from time to time.
 */
 #define SQLITE_STATUS_MEMORY_USED          0
 #define SQLITE_STATUS_PAGECACHE_USED       1
 #define SQLITE_STATUS_PAGECACHE_OVERFLOW   2
 #define SQLITE_STATUS_SCRATCH_USED         3  /* NOT USED */
 #define SQLITE_STATUS_SCRATCH_OVERFLOW     4  /* NOT USED */
 #define SQLITE_STATUS_MALLOC_SIZE          5
 #define SQLITE_STATUS_PARSER_STACK         6
 #define SQLITE_STATUS_PAGECACHE_SIZE       7
 #define SQLITE_STATUS_SCRATCH_SIZE         8  /* NOT USED */
 #define SQLITE_STATUS_MALLOC_COUNT         9
 
 /*
 ** CAPI3REF: Database Connection Status
 ** METHOD: sqlite3
 **
 ** ^This interface is used to retrieve runtime status information 
 ** about a single [database connection].  ^The first argument is the
 ** database connection object to be interrogated.  ^The second argument
 ** is an integer constant, taken from the set of
 ** [SQLITE_DBSTATUS options], that
 ** determines the parameter to interrogate.  The set of 
 ** [SQLITE_DBSTATUS options] is likely
 ** to grow in future releases of SQLite.
 **
 ** ^The current value of the requested parameter is written into *pCur
 ** and the highest instantaneous value is written into *pHiwtr.  ^If
 ** the resetFlg is true, then the highest instantaneous value is
 ** reset back down to the current value.
 **
 ** ^The sqlite3_db_status() routine returns SQLITE_OK on success and a
 ** non-zero [error code] on failure.
 **
 ** See also: [sqlite3_status()] and [sqlite3_stmt_status()].
 */
 SQLITE_API int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
 
 /*
 ** CAPI3REF: Status Parameters for database connections
 ** KEYWORDS: {SQLITE_DBSTATUS options}
 **
 ** These constants are the available integer "verbs" that can be passed as
 ** the second argument to the [sqlite3_db_status()] interface.
 **
 ** New verbs may be added in future releases of SQLite. Existing verbs
 ** might be discontinued. Applications should check the return code from
 ** [sqlite3_db_status()] to make sure that the call worked.
 ** The [sqlite3_db_status()] interface will return a non-zero error code
 ** if a discontinued or unsupported verb is invoked.
 **
 ** <dl>
 ** [[SQLITE_DBSTATUS_LOOKASIDE_USED]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_USED</dt>
 ** <dd>This parameter returns the number of lookaside memory slots currently
 ** checked out.</dd>)^
 **
 ** [[SQLITE_DBSTATUS_LOOKASIDE_HIT]] ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_HIT</dt>
 ** <dd>This parameter returns the number malloc attempts that were 
 ** satisfied using lookaside memory. Only the high-water value is meaningful;
 ** the current value is always zero.)^
 **
 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE]]
 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE</dt>
 ** <dd>This parameter returns the number malloc attempts that might have
 ** been satisfied using lookaside memory but failed due to the amount of
 ** memory requested being larger than the lookaside slot size.
 ** Only the high-water value is meaningful;
 ** the current value is always zero.)^
 **
 ** [[SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL]]
 ** ^(<dt>SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL</dt>
 ** <dd>This parameter returns the number malloc attempts that might have
 ** been satisfied using lookaside memory but failed due to all lookaside
 ** memory already being in use.
 ** Only the high-water value is meaningful;
 ** the current value is always zero.)^
 **
 ** [[SQLITE_DBSTATUS_CACHE_USED]] ^(<dt>SQLITE_DBSTATUS_CACHE_USED</dt>
 ** <dd>This parameter returns the approximate number of bytes of heap
 ** memory used by all pager caches associated with the database connection.)^
 ** ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_USED is always 0.
 **
 ** [[SQLITE_DBSTATUS_CACHE_USED_SHARED]] 
 ** ^(<dt>SQLITE_DBSTATUS_CACHE_USED_SHARED</dt>
 ** <dd>This parameter is similar to DBSTATUS_CACHE_USED, except that if a
 ** pager cache is shared between two or more connections the bytes of heap
 ** memory used by that pager cache is divided evenly between the attached
 ** connections.)^  In other words, if none of the pager caches associated
 ** with the database connection are shared, this request returns the same
 ** value as DBSTATUS_CACHE_USED. Or, if one or more or the pager caches are
 ** shared, the value returned by this call will be smaller than that returned
 ** by DBSTATUS_CACHE_USED. ^The highwater mark associated with
 ** SQLITE_DBSTATUS_CACHE_USED_SHARED is always 0.
 **
 ** [[SQLITE_DBSTATUS_SCHEMA_USED]] ^(<dt>SQLITE_DBSTATUS_SCHEMA_USED</dt>
 ** <dd>This parameter returns the approximate number of bytes of heap
 ** memory used to store the schema for all databases associated
 ** with the connection - main, temp, and any [ATTACH]-ed databases.)^ 
 ** ^The full amount of memory used by the schemas is reported, even if the
 ** schema memory is shared with other database connections due to
 ** [shared cache mode] being enabled.
 ** ^The highwater mark associated with SQLITE_DBSTATUS_SCHEMA_USED is always 0.
 **
 ** [[SQLITE_DBSTATUS_STMT_USED]] ^(<dt>SQLITE_DBSTATUS_STMT_USED</dt>
 ** <dd>This parameter returns the approximate number of bytes of heap
 ** and lookaside memory used by all prepared statements associated with
 ** the database connection.)^
 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
 ** </dd>
 **
 ** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
 ** <dd>This parameter returns the number of pager cache hits that have
 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 
 ** is always 0.
 ** </dd>
 **
 ** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
 ** <dd>This parameter returns the number of pager cache misses that have
 ** occurred.)^ ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 
 ** is always 0.
 ** </dd>
 **
 ** [[SQLITE_DBSTATUS_CACHE_WRITE]] ^(<dt>SQLITE_DBSTATUS_CACHE_WRITE</dt>
 ** <dd>This parameter returns the number of dirty cache entries that have
 ** been written to disk. Specifically, the number of pages written to the
 ** wal file in wal mode databases, or the number of pages written to the
 ** database file in rollback mode databases. Any pages written as part of
 ** transaction rollback or database recovery operations are not included.
 ** If an IO or other error occurs while writing a page to disk, the effect
 ** on subsequent SQLITE_DBSTATUS_CACHE_WRITE requests is undefined.)^ ^The
 ** highwater mark associated with SQLITE_DBSTATUS_CACHE_WRITE is always 0.
 ** </dd>
 **
 ** [[SQLITE_DBSTATUS_DEFERRED_FKS]] ^(<dt>SQLITE_DBSTATUS_DEFERRED_FKS</dt>
 ** <dd>This parameter returns zero for the current value if and only if
 ** all foreign key constraints (deferred or immediate) have been
 ** resolved.)^  ^The highwater mark is always 0.
 ** </dd>
 ** </dl>
 */
 #define SQLITE_DBSTATUS_LOOKASIDE_USED       0
 #define SQLITE_DBSTATUS_CACHE_USED           1
 #define SQLITE_DBSTATUS_SCHEMA_USED          2
 #define SQLITE_DBSTATUS_STMT_USED            3
 #define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
 #define SQLITE_DBSTATUS_CACHE_HIT            7
 #define SQLITE_DBSTATUS_CACHE_MISS           8
 #define SQLITE_DBSTATUS_CACHE_WRITE          9
 #define SQLITE_DBSTATUS_DEFERRED_FKS        10
 #define SQLITE_DBSTATUS_CACHE_USED_SHARED   11
 #define SQLITE_DBSTATUS_MAX                 11   /* Largest defined DBSTATUS */
 
 
 /*
 ** CAPI3REF: Prepared Statement Status
 ** METHOD: sqlite3_stmt
 **
 ** ^(Each prepared statement maintains various
 ** [SQLITE_STMTSTATUS counters] that measure the number
 ** of times it has performed specific operations.)^  These counters can
 ** be used to monitor the performance characteristics of the prepared
 ** statements.  For example, if the number of table steps greatly exceeds
 ** the number of table searches or result rows, that would tend to indicate
 ** that the prepared statement is using a full table scan rather than
 ** an index.  
 **
 ** ^(This interface is used to retrieve and reset counter values from
 ** a [prepared statement].  The first argument is the prepared statement
 ** object to be interrogated.  The second argument
 ** is an integer code for a specific [SQLITE_STMTSTATUS counter]
 ** to be interrogated.)^
 ** ^The current value of the requested counter is returned.
 ** ^If the resetFlg is true, then the counter is reset to zero after this
 ** interface call returns.
 **
 ** See also: [sqlite3_status()] and [sqlite3_db_status()].
 */
 SQLITE_API int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
 
 /*
 ** CAPI3REF: Status Parameters for prepared statements
 ** KEYWORDS: {SQLITE_STMTSTATUS counter} {SQLITE_STMTSTATUS counters}
 **
 ** These preprocessor macros define integer codes that name counter
 ** values associated with the [sqlite3_stmt_status()] interface.
 ** The meanings of the various counters are as follows:
 **
 ** <dl>
 ** [[SQLITE_STMTSTATUS_FULLSCAN_STEP]] <dt>SQLITE_STMTSTATUS_FULLSCAN_STEP</dt>
 ** <dd>^This is the number of times that SQLite has stepped forward in
 ** a table as part of a full table scan.  Large numbers for this counter
 ** may indicate opportunities for performance improvement through 
 ** careful use of indices.</dd>
 **
 ** [[SQLITE_STMTSTATUS_SORT]] <dt>SQLITE_STMTSTATUS_SORT</dt>
 ** <dd>^This is the number of sort operations that have occurred.
 ** A non-zero value in this counter may indicate an opportunity to
 ** improvement performance through careful use of indices.</dd>
 **
 ** [[SQLITE_STMTSTATUS_AUTOINDEX]] <dt>SQLITE_STMTSTATUS_AUTOINDEX</dt>
 ** <dd>^This is the number of rows inserted into transient indices that
 ** were created automatically in order to help joins run faster.
 ** A non-zero value in this counter may indicate an opportunity to
 ** improvement performance by adding permanent indices that do not
 ** need to be reinitialized each time the statement is run.</dd>
 **
 ** [[SQLITE_STMTSTATUS_VM_STEP]] <dt>SQLITE_STMTSTATUS_VM_STEP</dt>
 ** <dd>^This is the number of virtual machine operations executed
 ** by the prepared statement if that number is less than or equal
 ** to 2147483647.  The number of virtual machine operations can be 
 ** used as a proxy for the total work done by the prepared statement.
 ** If the number of virtual machine operations exceeds 2147483647
 ** then the value returned by this statement status code is undefined.
 **
 ** [[SQLITE_STMTSTATUS_REPREPARE]] <dt>SQLITE_STMTSTATUS_REPREPARE</dt>
 ** <dd>^This is the number of times that the prepare statement has been
 ** automatically regenerated due to schema changes or change to 
 ** [bound parameters] that might affect the query plan.
 **
 ** [[SQLITE_STMTSTATUS_RUN]] <dt>SQLITE_STMTSTATUS_RUN</dt>
 ** <dd>^This is the number of times that the prepared statement has
 ** been run.  A single "run" for the purposes of this counter is one
 ** or more calls to [sqlite3_step()] followed by a call to [sqlite3_reset()].
 ** The counter is incremented on the first [sqlite3_step()] call of each
 ** cycle.
 **
 ** [[SQLITE_STMTSTATUS_MEMUSED]] <dt>SQLITE_STMTSTATUS_MEMUSED</dt>
 ** <dd>^This is the approximate number of bytes of heap memory
 ** used to store the prepared statement.  ^This value is not actually
 ** a counter, and so the resetFlg parameter to sqlite3_stmt_status()
 ** is ignored when the opcode is SQLITE_STMTSTATUS_MEMUSED.
 ** </dd>
 ** </dl>
 */
 #define SQLITE_STMTSTATUS_FULLSCAN_STEP     1
 #define SQLITE_STMTSTATUS_SORT              2
 #define SQLITE_STMTSTATUS_AUTOINDEX         3
 #define SQLITE_STMTSTATUS_VM_STEP           4
 #define SQLITE_STMTSTATUS_REPREPARE         5
 #define SQLITE_STMTSTATUS_RUN               6
 #define SQLITE_STMTSTATUS_MEMUSED           99
 
 /*
 ** CAPI3REF: Custom Page Cache Object
 **
 ** The sqlite3_pcache type is opaque.  It is implemented by
 ** the pluggable module.  The SQLite core has no knowledge of
 ** its size or internal structure and never deals with the
 ** sqlite3_pcache object except by holding and passing pointers
 ** to the object.
 **
 ** See [sqlite3_pcache_methods2] for additional information.
 */
 typedef struct sqlite3_pcache sqlite3_pcache;
 
 /*
 ** CAPI3REF: Custom Page Cache Object
 **
 ** The sqlite3_pcache_page object represents a single page in the
 ** page cache.  The page cache will allocate instances of this
 ** object.  Various methods of the page cache use pointers to instances
 ** of this object as parameters or as their return value.
 **
 ** See [sqlite3_pcache_methods2] for additional information.
 */
 typedef struct sqlite3_pcache_page sqlite3_pcache_page;
 struct sqlite3_pcache_page {
   void *pBuf;        /* The content of the page */
   void *pExtra;      /* Extra information associated with the page */
 };
 
 /*
 ** CAPI3REF: Application Defined Page Cache.
 ** KEYWORDS: {page cache}
 **
 ** ^(The [sqlite3_config]([SQLITE_CONFIG_PCACHE2], ...) interface can
 ** register an alternative page cache implementation by passing in an 
 ** instance of the sqlite3_pcache_methods2 structure.)^
 ** In many applications, most of the heap memory allocated by 
 ** SQLite is used for the page cache.
 ** By implementing a 
 ** custom page cache using this API, an application can better control
 ** the amount of memory consumed by SQLite, the way in which 
 ** that memory is allocated and released, and the policies used to 
 ** determine exactly which parts of a database file are cached and for 
 ** how long.
 **
 ** The alternative page cache mechanism is an
 ** extreme measure that is only needed by the most demanding applications.
 ** The built-in page cache is recommended for most uses.
 **
 ** ^(The contents of the sqlite3_pcache_methods2 structure are copied to an
 ** internal buffer by SQLite within the call to [sqlite3_config].  Hence
 ** the application may discard the parameter after the call to
 ** [sqlite3_config()] returns.)^
 **
 ** [[the xInit() page cache method]]
 ** ^(The xInit() method is called once for each effective 
 ** call to [sqlite3_initialize()])^
 ** (usually only once during the lifetime of the process). ^(The xInit()
 ** method is passed a copy of the sqlite3_pcache_methods2.pArg value.)^
 ** The intent of the xInit() method is to set up global data structures 
 ** required by the custom page cache implementation. 
 ** ^(If the xInit() method is NULL, then the 
 ** built-in default page cache is used instead of the application defined
 ** page cache.)^
 **
 ** [[the xShutdown() page cache method]]
 ** ^The xShutdown() method is called by [sqlite3_shutdown()].
 ** It can be used to clean up 
 ** any outstanding resources before process shutdown, if required.
 ** ^The xShutdown() method may be NULL.
 **
 ** ^SQLite automatically serializes calls to the xInit method,
 ** so the xInit method need not be threadsafe.  ^The
 ** xShutdown method is only called from [sqlite3_shutdown()] so it does
 ** not need to be threadsafe either.  All other methods must be threadsafe
 ** in multithreaded applications.
 **
 ** ^SQLite will never invoke xInit() more than once without an intervening
 ** call to xShutdown().
 **
 ** [[the xCreate() page cache methods]]
 ** ^SQLite invokes the xCreate() method to construct a new cache instance.
 ** SQLite will typically create one cache instance for each open database file,
 ** though this is not guaranteed. ^The
 ** first parameter, szPage, is the size in bytes of the pages that must
 ** be allocated by the cache.  ^szPage will always a power of two.  ^The
 ** second parameter szExtra is a number of bytes of extra storage 
 ** associated with each page cache entry.  ^The szExtra parameter will
 ** a number less than 250.  SQLite will use the
 ** extra szExtra bytes on each page to store metadata about the underlying
 ** database page on disk.  The value passed into szExtra depends
 ** on the SQLite version, the target platform, and how SQLite was compiled.
 ** ^The third argument to xCreate(), bPurgeable, is true if the cache being
 ** created will be used to cache database pages of a file stored on disk, or
 ** false if it is used for an in-memory database. The cache implementation
 ** does not have to do anything special based with the value of bPurgeable;
 ** it is purely advisory.  ^On a cache where bPurgeable is false, SQLite will
 ** never invoke xUnpin() except to deliberately delete a page.
 ** ^In other words, calls to xUnpin() on a cache with bPurgeable set to
 ** false will always have the "discard" flag set to true.  
 ** ^Hence, a cache created with bPurgeable false will
 ** never contain any unpinned pages.
 **
 ** [[the xCachesize() page cache method]]
 ** ^(The xCachesize() method may be called at any time by SQLite to set the
 ** suggested maximum cache-size (number of pages stored by) the cache
 ** instance passed as the first argument. This is the value configured using
 ** the SQLite "[PRAGMA cache_size]" command.)^  As with the bPurgeable
 ** parameter, the implementation is not required to do anything with this
 ** value; it is advisory only.
 **
 ** [[the xPagecount() page cache methods]]
 ** The xPagecount() method must return the number of pages currently
 ** stored in the cache, both pinned and unpinned.
 ** 
 ** [[the xFetch() page cache methods]]
 ** The xFetch() method locates a page in the cache and returns a pointer to 
 ** an sqlite3_pcache_page object associated with that page, or a NULL pointer.
 ** The pBuf element of the returned sqlite3_pcache_page object will be a
 ** pointer to a buffer of szPage bytes used to store the content of a 
 ** single database page.  The pExtra element of sqlite3_pcache_page will be
 ** a pointer to the szExtra bytes of extra storage that SQLite has requested
 ** for each entry in the page cache.
 **
 ** The page to be fetched is determined by the key. ^The minimum key value
 ** is 1.  After it has been retrieved using xFetch, the page is considered
 ** to be "pinned".
 **
 ** If the requested page is already in the page cache, then the page cache
 ** implementation must return a pointer to the page buffer with its content
 ** intact.  If the requested page is not already in the cache, then the
 ** cache implementation should use the value of the createFlag
 ** parameter to help it determined what action to take:
 **
 ** <table border=1 width=85% align=center>
 ** <tr><th> createFlag <th> Behavior when page is not already in cache
 ** <tr><td> 0 <td> Do not allocate a new page.  Return NULL.
 ** <tr><td> 1 <td> Allocate a new page if it easy and convenient to do so.
 **                 Otherwise return NULL.
 ** <tr><td> 2 <td> Make every effort to allocate a new page.  Only return
 **                 NULL if allocating a new page is effectively impossible.
 ** </table>
 **
 ** ^(SQLite will normally invoke xFetch() with a createFlag of 0 or 1.  SQLite
 ** will only use a createFlag of 2 after a prior call with a createFlag of 1
 ** failed.)^  In between the to xFetch() calls, SQLite may
 ** attempt to unpin one or more cache pages by spilling the content of
 ** pinned pages to disk and synching the operating system disk cache.
 **
 ** [[the xUnpin() page cache method]]
 ** ^xUnpin() is called by SQLite with a pointer to a currently pinned page
 ** as its second argument.  If the third parameter, discard, is non-zero,
 ** then the page must be evicted from the cache.
 ** ^If the discard parameter is
 ** zero, then the page may be discarded or retained at the discretion of
 ** page cache implementation. ^The page cache implementation
 ** may choose to evict unpinned pages at any time.
 **
 ** The cache must not perform any reference counting. A single 
 ** call to xUnpin() unpins the page regardless of the number of prior calls 
 ** to xFetch().
 **
 ** [[the xRekey() page cache methods]]
 ** The xRekey() method is used to change the key value associated with the
 ** page passed as the second argument. If the cache
 ** previously contains an entry associated with newKey, it must be
 ** discarded. ^Any prior cache entry associated with newKey is guaranteed not
 ** to be pinned.
 **
 ** When SQLite calls the xTruncate() method, the cache must discard all
 ** existing cache entries with page numbers (keys) greater than or equal
 ** to the value of the iLimit parameter passed to xTruncate(). If any
 ** of these pages are pinned, they are implicitly unpinned, meaning that
 ** they can be safely discarded.
 **
 ** [[the xDestroy() page cache method]]
 ** ^The xDestroy() method is used to delete a cache allocated by xCreate().
 ** All resources associated with the specified cache should be freed. ^After
 ** calling the xDestroy() method, SQLite considers the [sqlite3_pcache*]
 ** handle invalid, and will not use it with any other sqlite3_pcache_methods2
 ** functions.
 **
 ** [[the xShrink() page cache method]]
 ** ^SQLite invokes the xShrink() method when it wants the page cache to
 ** free up as much of heap memory as possible.  The page cache implementation
 ** is not obligated to free any memory, but well-behaved implementations should
 ** do their best.
 */
 typedef struct sqlite3_pcache_methods2 sqlite3_pcache_methods2;
 struct sqlite3_pcache_methods2 {
   int iVersion;
   void *pArg;
   int (*xInit)(void*);
   void (*xShutdown)(void*);
   sqlite3_pcache *(*xCreate)(int szPage, int szExtra, int bPurgeable);
   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
   int (*xPagecount)(sqlite3_pcache*);
   sqlite3_pcache_page *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
   void (*xUnpin)(sqlite3_pcache*, sqlite3_pcache_page*, int discard);
   void (*xRekey)(sqlite3_pcache*, sqlite3_pcache_page*, 
       unsigned oldKey, unsigned newKey);
   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
   void (*xDestroy)(sqlite3_pcache*);
   void (*xShrink)(sqlite3_pcache*);
 };
 
 /*
 ** This is the obsolete pcache_methods object that has now been replaced
 ** by sqlite3_pcache_methods2.  This object is not used by SQLite.  It is
 ** retained in the header file for backwards compatibility only.
 */
 typedef struct sqlite3_pcache_methods sqlite3_pcache_methods;
 struct sqlite3_pcache_methods {
   void *pArg;
   int (*xInit)(void*);
   void (*xShutdown)(void*);
   sqlite3_pcache *(*xCreate)(int szPage, int bPurgeable);
   void (*xCachesize)(sqlite3_pcache*, int nCachesize);
   int (*xPagecount)(sqlite3_pcache*);
   void *(*xFetch)(sqlite3_pcache*, unsigned key, int createFlag);
   void (*xUnpin)(sqlite3_pcache*, void*, int discard);
   void (*xRekey)(sqlite3_pcache*, void*, unsigned oldKey, unsigned newKey);
   void (*xTruncate)(sqlite3_pcache*, unsigned iLimit);
   void (*xDestroy)(sqlite3_pcache*);
 };
 
 
 /*
 ** CAPI3REF: Online Backup Object
 **
 ** The sqlite3_backup object records state information about an ongoing
 ** online backup operation.  ^The sqlite3_backup object is created by
 ** a call to [sqlite3_backup_init()] and is destroyed by a call to
 ** [sqlite3_backup_finish()].
 **
 ** See Also: [Using the SQLite Online Backup API]
 */
 typedef struct sqlite3_backup sqlite3_backup;
 
 /*
 ** CAPI3REF: Online Backup API.
 **
 ** The backup API copies the content of one database into another.
 ** It is useful either for creating backups of databases or
 ** for copying in-memory databases to or from persistent files. 
 **
 ** See Also: [Using the SQLite Online Backup API]
 **
 ** ^SQLite holds a write transaction open on the destination database file
 ** for the duration of the backup operation.
 ** ^The source database is read-locked only while it is being read;
 ** it is not locked continuously for the entire backup operation.
 ** ^Thus, the backup may be performed on a live source database without
 ** preventing other database connections from
 ** reading or writing to the source database while the backup is underway.
 ** 
 ** ^(To perform a backup operation: 
 **   <ol>
 **     <li><b>sqlite3_backup_init()</b> is called once to initialize the
 **         backup, 
 **     <li><b>sqlite3_backup_step()</b> is called one or more times to transfer 
 **         the data between the two databases, and finally
 **     <li><b>sqlite3_backup_finish()</b> is called to release all resources 
 **         associated with the backup operation. 
 **   </ol>)^
 ** There should be exactly one call to sqlite3_backup_finish() for each
 ** successful call to sqlite3_backup_init().
 **
 ** [[sqlite3_backup_init()]] <b>sqlite3_backup_init()</b>
 **
 ** ^The D and N arguments to sqlite3_backup_init(D,N,S,M) are the 
 ** [database connection] associated with the destination database 
 ** and the database name, respectively.
 ** ^The database name is "main" for the main database, "temp" for the
 ** temporary database, or the name specified after the AS keyword in
 ** an [ATTACH] statement for an attached database.
 ** ^The S and M arguments passed to 
 ** sqlite3_backup_init(D,N,S,M) identify the [database connection]
 ** and database name of the source database, respectively.
 ** ^The source and destination [database connections] (parameters S and D)
 ** must be different or else sqlite3_backup_init(D,N,S,M) will fail with
 ** an error.
 **
 ** ^A call to sqlite3_backup_init() will fail, returning NULL, if 
 ** there is already a read or read-write transaction open on the 
 ** destination database.
 **
 ** ^If an error occurs within sqlite3_backup_init(D,N,S,M), then NULL is
 ** returned and an error code and error message are stored in the
 ** destination [database connection] D.
 ** ^The error code and message for the failed call to sqlite3_backup_init()
 ** can be retrieved using the [sqlite3_errcode()], [sqlite3_errmsg()], and/or
 ** [sqlite3_errmsg16()] functions.
 ** ^A successful call to sqlite3_backup_init() returns a pointer to an
 ** [sqlite3_backup] object.
 ** ^The [sqlite3_backup] object may be used with the sqlite3_backup_step() and
 ** sqlite3_backup_finish() functions to perform the specified backup 
 ** operation.
 **
 ** [[sqlite3_backup_step()]] <b>sqlite3_backup_step()</b>
 **
 ** ^Function sqlite3_backup_step(B,N) will copy up to N pages between 
 ** the source and destination databases specified by [sqlite3_backup] object B.
 ** ^If N is negative, all remaining source pages are copied. 
 ** ^If sqlite3_backup_step(B,N) successfully copies N pages and there
 ** are still more pages to be copied, then the function returns [SQLITE_OK].
 ** ^If sqlite3_backup_step(B,N) successfully finishes copying all pages
 ** from source to destination, then it returns [SQLITE_DONE].
 ** ^If an error occurs while running sqlite3_backup_step(B,N),
 ** then an [error code] is returned. ^As well as [SQLITE_OK] and
 ** [SQLITE_DONE], a call to sqlite3_backup_step() may return [SQLITE_READONLY],
 ** [SQLITE_NOMEM], [SQLITE_BUSY], [SQLITE_LOCKED], or an
 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX] extended error code.
 **
 ** ^(The sqlite3_backup_step() might return [SQLITE_READONLY] if
 ** <ol>
 ** <li> the destination database was opened read-only, or
 ** <li> the destination database is using write-ahead-log journaling
 ** and the destination and source page sizes differ, or
 ** <li> the destination database is an in-memory database and the
 ** destination and source page sizes differ.
 ** </ol>)^
 **
 ** ^If sqlite3_backup_step() cannot obtain a required file-system lock, then
 ** the [sqlite3_busy_handler | busy-handler function]
 ** is invoked (if one is specified). ^If the 
 ** busy-handler returns non-zero before the lock is available, then 
 ** [SQLITE_BUSY] is returned to the caller. ^In this case the call to
 ** sqlite3_backup_step() can be retried later. ^If the source
 ** [database connection]
 ** is being used to write to the source database when sqlite3_backup_step()
 ** is called, then [SQLITE_LOCKED] is returned immediately. ^Again, in this
 ** case the call to sqlite3_backup_step() can be retried later on. ^(If
 ** [SQLITE_IOERR_ACCESS | SQLITE_IOERR_XXX], [SQLITE_NOMEM], or
 ** [SQLITE_READONLY] is returned, then 
 ** there is no point in retrying the call to sqlite3_backup_step(). These 
 ** errors are considered fatal.)^  The application must accept 
 ** that the backup operation has failed and pass the backup operation handle 
 ** to the sqlite3_backup_finish() to release associated resources.
 **
 ** ^The first call to sqlite3_backup_step() obtains an exclusive lock
 ** on the destination file. ^The exclusive lock is not released until either 
 ** sqlite3_backup_finish() is called or the backup operation is complete 
 ** and sqlite3_backup_step() returns [SQLITE_DONE].  ^Every call to
 ** sqlite3_backup_step() obtains a [shared lock] on the source database that
 ** lasts for the duration of the sqlite3_backup_step() call.
 ** ^Because the source database is not locked between calls to
 ** sqlite3_backup_step(), the source database may be modified mid-way
 ** through the backup process.  ^If the source database is modified by an
 ** external process or via a database connection other than the one being
 ** used by the backup operation, then the backup will be automatically
 ** restarted by the next call to sqlite3_backup_step(). ^If the source 
 ** database is modified by the using the same database connection as is used
 ** by the backup operation, then the backup database is automatically
 ** updated at the same time.
 **
 ** [[sqlite3_backup_finish()]] <b>sqlite3_backup_finish()</b>
 **
 ** When sqlite3_backup_step() has returned [SQLITE_DONE], or when the 
 ** application wishes to abandon the backup operation, the application
 ** should destroy the [sqlite3_backup] by passing it to sqlite3_backup_finish().
 ** ^The sqlite3_backup_finish() interfaces releases all
 ** resources associated with the [sqlite3_backup] object. 
 ** ^If sqlite3_backup_step() has not yet returned [SQLITE_DONE], then any
 ** active write-transaction on the destination database is rolled back.
 ** The [sqlite3_backup] object is invalid
 ** and may not be used following a call to sqlite3_backup_finish().
 **
 ** ^The value returned by sqlite3_backup_finish is [SQLITE_OK] if no
 ** sqlite3_backup_step() errors occurred, regardless or whether or not
 ** sqlite3_backup_step() completed.
 ** ^If an out-of-memory condition or IO error occurred during any prior
 ** sqlite3_backup_step() call on the same [sqlite3_backup] object, then
 ** sqlite3_backup_finish() returns the corresponding [error code].
 **
 ** ^A return of [SQLITE_BUSY] or [SQLITE_LOCKED] from sqlite3_backup_step()
 ** is not a permanent error and does not affect the return value of
 ** sqlite3_backup_finish().
 **
 ** [[sqlite3_backup_remaining()]] [[sqlite3_backup_pagecount()]]
 ** <b>sqlite3_backup_remaining() and sqlite3_backup_pagecount()</b>
 **
 ** ^The sqlite3_backup_remaining() routine returns the number of pages still
 ** to be backed up at the conclusion of the most recent sqlite3_backup_step().
 ** ^The sqlite3_backup_pagecount() routine returns the total number of pages
 ** in the source database at the conclusion of the most recent
 ** sqlite3_backup_step().
 ** ^(The values returned by these functions are only updated by
 ** sqlite3_backup_step(). If the source database is modified in a way that
 ** changes the size of the source database or the number of pages remaining,
 ** those changes are not reflected in the output of sqlite3_backup_pagecount()
 ** and sqlite3_backup_remaining() until after the next
 ** sqlite3_backup_step().)^
 **
 ** <b>Concurrent Usage of Database Handles</b>
 **
 ** ^The source [database connection] may be used by the application for other
 ** purposes while a backup operation is underway or being initialized.
 ** ^If SQLite is compiled and configured to support threadsafe database
 ** connections, then the source database connection may be used concurrently
 ** from within other threads.
 **
 ** However, the application must guarantee that the destination 
 ** [database connection] is not passed to any other API (by any thread) after 
 ** sqlite3_backup_init() is called and before the corresponding call to
 ** sqlite3_backup_finish().  SQLite does not currently check to see
 ** if the application incorrectly accesses the destination [database connection]
 ** and so no error code is reported, but the operations may malfunction
 ** nevertheless.  Use of the destination database connection while a
 ** backup is in progress might also also cause a mutex deadlock.
 **
 ** If running in [shared cache mode], the application must
 ** guarantee that the shared cache used by the destination database
 ** is not accessed while the backup is running. In practice this means
 ** that the application must guarantee that the disk file being 
 ** backed up to is not accessed by any connection within the process,
 ** not just the specific connection that was passed to sqlite3_backup_init().
 **
 ** The [sqlite3_backup] object itself is partially threadsafe. Multiple 
 ** threads may safely make multiple concurrent calls to sqlite3_backup_step().
 ** However, the sqlite3_backup_remaining() and sqlite3_backup_pagecount()
 ** APIs are not strictly speaking threadsafe. If they are invoked at the
 ** same time as another thread is invoking sqlite3_backup_step() it is
 ** possible that they return invalid values.
 */
 SQLITE_API sqlite3_backup *sqlite3_backup_init(
   sqlite3 *pDest,                        /* Destination database handle */
   const char *zDestName,                 /* Destination database name */
   sqlite3 *pSource,                      /* Source database handle */
   const char *zSourceName                /* Source database name */
 );
 SQLITE_API int sqlite3_backup_step(sqlite3_backup *p, int nPage);
 SQLITE_API int sqlite3_backup_finish(sqlite3_backup *p);
 SQLITE_API int sqlite3_backup_remaining(sqlite3_backup *p);
 SQLITE_API int sqlite3_backup_pagecount(sqlite3_backup *p);
 
 /*
 ** CAPI3REF: Unlock Notification
 ** METHOD: sqlite3
 **
 ** ^When running in shared-cache mode, a database operation may fail with
 ** an [SQLITE_LOCKED] error if the required locks on the shared-cache or
 ** individual tables within the shared-cache cannot be obtained. See
 ** [SQLite Shared-Cache Mode] for a description of shared-cache locking. 
 ** ^This API may be used to register a callback that SQLite will invoke 
 ** when the connection currently holding the required lock relinquishes it.
 ** ^This API is only available if the library was compiled with the
 ** [SQLITE_ENABLE_UNLOCK_NOTIFY] C-preprocessor symbol defined.
 **
 ** See Also: [Using the SQLite Unlock Notification Feature].
 **
 ** ^Shared-cache locks are released when a database connection concludes
 ** its current transaction, either by committing it or rolling it back. 
 **
 ** ^When a connection (known as the blocked connection) fails to obtain a
 ** shared-cache lock and SQLITE_LOCKED is returned to the caller, the
 ** identity of the database connection (the blocking connection) that
 ** has locked the required resource is stored internally. ^After an 
 ** application receives an SQLITE_LOCKED error, it may call the
 ** sqlite3_unlock_notify() method with the blocked connection handle as 
 ** the first argument to register for a callback that will be invoked
 ** when the blocking connections current transaction is concluded. ^The
 ** callback is invoked from within the [sqlite3_step] or [sqlite3_close]
 ** call that concludes the blocking connections transaction.
 **
 ** ^(If sqlite3_unlock_notify() is called in a multi-threaded application,
 ** there is a chance that the blocking connection will have already
 ** concluded its transaction by the time sqlite3_unlock_notify() is invoked.
 ** If this happens, then the specified callback is invoked immediately,
 ** from within the call to sqlite3_unlock_notify().)^
 **
 ** ^If the blocked connection is attempting to obtain a write-lock on a
 ** shared-cache table, and more than one other connection currently holds
 ** a read-lock on the same table, then SQLite arbitrarily selects one of 
 ** the other connections to use as the blocking connection.
 **
 ** ^(There may be at most one unlock-notify callback registered by a 
 ** blocked connection. If sqlite3_unlock_notify() is called when the
 ** blocked connection already has a registered unlock-notify callback,
 ** then the new callback replaces the old.)^ ^If sqlite3_unlock_notify() is
 ** called with a NULL pointer as its second argument, then any existing
 ** unlock-notify callback is canceled. ^The blocked connections 
 ** unlock-notify callback may also be canceled by closing the blocked
 ** connection using [sqlite3_close()].
 **
 ** The unlock-notify callback is not reentrant. If an application invokes
 ** any sqlite3_xxx API functions from within an unlock-notify callback, a
 ** crash or deadlock may be the result.
 **
 ** ^Unless deadlock is detected (see below), sqlite3_unlock_notify() always
 ** returns SQLITE_OK.
 **
 ** <b>Callback Invocation Details</b>
 **
 ** When an unlock-notify callback is registered, the application provides a 
 ** single void* pointer that is passed to the callback when it is invoked.
 ** However, the signature of the callback function allows SQLite to pass
 ** it an array of void* context pointers. The first argument passed to
 ** an unlock-notify callback is a pointer to an array of void* pointers,
 ** and the second is the number of entries in the array.
 **
 ** When a blocking connections transaction is concluded, there may be
 ** more than one blocked connection that has registered for an unlock-notify
 ** callback. ^If two or more such blocked connections have specified the
 ** same callback function, then instead of invoking the callback function
 ** multiple times, it is invoked once with the set of void* context pointers
 ** specified by the blocked connections bundled together into an array.
 ** This gives the application an opportunity to prioritize any actions 
 ** related to the set of unblocked database connections.
 **
 ** <b>Deadlock Detection</b>
 **
 ** Assuming that after registering for an unlock-notify callback a 
 ** database waits for the callback to be issued before taking any further
 ** action (a reasonable assumption), then using this API may cause the
 ** application to deadlock. For example, if connection X is waiting for
 ** connection Y's transaction to be concluded, and similarly connection
 ** Y is waiting on connection X's transaction, then neither connection
 ** will proceed and the system may remain deadlocked indefinitely.
 **
 ** To avoid this scenario, the sqlite3_unlock_notify() performs deadlock
 ** detection. ^If a given call to sqlite3_unlock_notify() would put the
 ** system in a deadlocked state, then SQLITE_LOCKED is returned and no
 ** unlock-notify callback is registered. The system is said to be in
 ** a deadlocked state if connection A has registered for an unlock-notify
 ** callback on the conclusion of connection B's transaction, and connection
 ** B has itself registered for an unlock-notify callback when connection
 ** A's transaction is concluded. ^Indirect deadlock is also detected, so
 ** the system is also considered to be deadlocked if connection B has
 ** registered for an unlock-notify callback on the conclusion of connection
 ** C's transaction, where connection C is waiting on connection A. ^Any
 ** number of levels of indirection are allowed.
 **
 ** <b>The "DROP TABLE" Exception</b>
 **
 ** When a call to [sqlite3_step()] returns SQLITE_LOCKED, it is almost 
 ** always appropriate to call sqlite3_unlock_notify(). There is however,
 ** one exception. When executing a "DROP TABLE" or "DROP INDEX" statement,
 ** SQLite checks if there are any currently executing SELECT statements
 ** that belong to the same connection. If there are, SQLITE_LOCKED is
 ** returned. In this case there is no "blocking connection", so invoking
 ** sqlite3_unlock_notify() results in the unlock-notify callback being
 ** invoked immediately. If the application then re-attempts the "DROP TABLE"
 ** or "DROP INDEX" query, an infinite loop might be the result.
 **
 ** One way around this problem is to check the extended error code returned
 ** by an sqlite3_step() call. ^(If there is a blocking connection, then the
 ** extended error code is set to SQLITE_LOCKED_SHAREDCACHE. Otherwise, in
 ** the special "DROP TABLE/INDEX" case, the extended error code is just 
 ** SQLITE_LOCKED.)^
 */
 SQLITE_API int sqlite3_unlock_notify(
   sqlite3 *pBlocked,                          /* Waiting connection */
   void (*xNotify)(void **apArg, int nArg),    /* Callback function to invoke */
   void *pNotifyArg                            /* Argument to pass to xNotify */
 );
 
 
 /*
 ** CAPI3REF: String Comparison
 **
 ** ^The [sqlite3_stricmp()] and [sqlite3_strnicmp()] APIs allow applications
 ** and extensions to compare the contents of two buffers containing UTF-8
 ** strings in a case-independent fashion, using the same definition of "case
 ** independence" that SQLite uses internally when comparing identifiers.
 */
 SQLITE_API int sqlite3_stricmp(const char *, const char *);
 SQLITE_API int sqlite3_strnicmp(const char *, const char *, int);
 
 /*
 ** CAPI3REF: String Globbing
 *
 ** ^The [sqlite3_strglob(P,X)] interface returns zero if and only if
 ** string X matches the [GLOB] pattern P.
 ** ^The definition of [GLOB] pattern matching used in
 ** [sqlite3_strglob(P,X)] is the same as for the "X GLOB P" operator in the
 ** SQL dialect understood by SQLite.  ^The [sqlite3_strglob(P,X)] function
 ** is case sensitive.
 **
 ** Note that this routine returns zero on a match and non-zero if the strings
 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
 **
 ** See also: [sqlite3_strlike()].
 */
 SQLITE_API int sqlite3_strglob(const char *zGlob, const char *zStr);
 
 /*
 ** CAPI3REF: String LIKE Matching
 *
 ** ^The [sqlite3_strlike(P,X,E)] interface returns zero if and only if
 ** string X matches the [LIKE] pattern P with escape character E.
 ** ^The definition of [LIKE] pattern matching used in
 ** [sqlite3_strlike(P,X,E)] is the same as for the "X LIKE P ESCAPE E"
 ** operator in the SQL dialect understood by SQLite.  ^For "X LIKE P" without
 ** the ESCAPE clause, set the E parameter of [sqlite3_strlike(P,X,E)] to 0.
 ** ^As with the LIKE operator, the [sqlite3_strlike(P,X,E)] function is case
 ** insensitive - equivalent upper and lower case ASCII characters match
 ** one another.
 **
 ** ^The [sqlite3_strlike(P,X,E)] function matches Unicode characters, though
 ** only ASCII characters are case folded.
 **
 ** Note that this routine returns zero on a match and non-zero if the strings
 ** do not match, the same as [sqlite3_stricmp()] and [sqlite3_strnicmp()].
 **
 ** See also: [sqlite3_strglob()].
 */
 SQLITE_API int sqlite3_strlike(const char *zGlob, const char *zStr, unsigned int cEsc);
 
 /*
 ** CAPI3REF: Error Logging Interface
 **
 ** ^The [sqlite3_log()] interface writes a message into the [error log]
 ** established by the [SQLITE_CONFIG_LOG] option to [sqlite3_config()].
 ** ^If logging is enabled, the zFormat string and subsequent arguments are
 ** used with [sqlite3_snprintf()] to generate the final output string.
 **
 ** The sqlite3_log() interface is intended for use by extensions such as
 ** virtual tables, collating functions, and SQL functions.  While there is
 ** nothing to prevent an application from calling sqlite3_log(), doing so
 ** is considered bad form.
 **
 ** The zFormat string must not be NULL.
 **
 ** To avoid deadlocks and other threading problems, the sqlite3_log() routine
 ** will not use dynamically allocated memory.  The log message is stored in
 ** a fixed-length buffer on the stack.  If the log message is longer than
 ** a few hundred characters, it will be truncated to the length of the
 ** buffer.
 */
 SQLITE_API void sqlite3_log(int iErrCode, const char *zFormat, ...);
 
 /*
 ** CAPI3REF: Write-Ahead Log Commit Hook
 ** METHOD: sqlite3
 **
 ** ^The [sqlite3_wal_hook()] function is used to register a callback that
 ** is invoked each time data is committed to a database in wal mode.
 **
 ** ^(The callback is invoked by SQLite after the commit has taken place and 
 ** the associated write-lock on the database released)^, so the implementation 
 ** may read, write or [checkpoint] the database as required.
 **
 ** ^The first parameter passed to the callback function when it is invoked
 ** is a copy of the third parameter passed to sqlite3_wal_hook() when
 ** registering the callback. ^The second is a copy of the database handle.
 ** ^The third parameter is the name of the database that was written to -
 ** either "main" or the name of an [ATTACH]-ed database. ^The fourth parameter
 ** is the number of pages currently in the write-ahead log file,
 ** including those that were just committed.
 **
 ** The callback function should normally return [SQLITE_OK].  ^If an error
 ** code is returned, that error will propagate back up through the
 ** SQLite code base to cause the statement that provoked the callback
 ** to report an error, though the commit will have still occurred. If the
 ** callback returns [SQLITE_ROW] or [SQLITE_DONE], or if it returns a value
 ** that does not correspond to any valid SQLite error code, the results
 ** are undefined.
 **
 ** A single database handle may have at most a single write-ahead log callback 
 ** registered at one time. ^Calling [sqlite3_wal_hook()] replaces any
 ** previously registered write-ahead log callback. ^Note that the
 ** [sqlite3_wal_autocheckpoint()] interface and the
 ** [wal_autocheckpoint pragma] both invoke [sqlite3_wal_hook()] and will
 ** overwrite any prior [sqlite3_wal_hook()] settings.
 */
 SQLITE_API void *sqlite3_wal_hook(
   sqlite3*, 
   int(*)(void *,sqlite3*,const char*,int),
   void*
 );
 
 /*
 ** CAPI3REF: Configure an auto-checkpoint
 ** METHOD: sqlite3
 **
 ** ^The [sqlite3_wal_autocheckpoint(D,N)] is a wrapper around
 ** [sqlite3_wal_hook()] that causes any database on [database connection] D
 ** to automatically [checkpoint]
 ** after committing a transaction if there are N or
 ** more frames in the [write-ahead log] file.  ^Passing zero or 
 ** a negative value as the nFrame parameter disables automatic
 ** checkpoints entirely.
 **
 ** ^The callback registered by this function replaces any existing callback
 ** registered using [sqlite3_wal_hook()].  ^Likewise, registering a callback
 ** using [sqlite3_wal_hook()] disables the automatic checkpoint mechanism
 ** configured by this function.
 **
 ** ^The [wal_autocheckpoint pragma] can be used to invoke this interface
 ** from SQL.
 **
 ** ^Checkpoints initiated by this mechanism are
 ** [sqlite3_wal_checkpoint_v2|PASSIVE].
 **
 ** ^Every new [database connection] defaults to having the auto-checkpoint
 ** enabled with a threshold of 1000 or [SQLITE_DEFAULT_WAL_AUTOCHECKPOINT]
 ** pages.  The use of this interface
 ** is only necessary if the default setting is found to be suboptimal
 ** for a particular application.
 */
 SQLITE_API int sqlite3_wal_autocheckpoint(sqlite3 *db, int N);
 
 /*
 ** CAPI3REF: Checkpoint a database
 ** METHOD: sqlite3
 **
 ** ^(The sqlite3_wal_checkpoint(D,X) is equivalent to
 ** [sqlite3_wal_checkpoint_v2](D,X,[SQLITE_CHECKPOINT_PASSIVE],0,0).)^
 **
 ** In brief, sqlite3_wal_checkpoint(D,X) causes the content in the 
 ** [write-ahead log] for database X on [database connection] D to be
 ** transferred into the database file and for the write-ahead log to
 ** be reset.  See the [checkpointing] documentation for addition
 ** information.
 **
 ** This interface used to be the only way to cause a checkpoint to
 ** occur.  But then the newer and more powerful [sqlite3_wal_checkpoint_v2()]
 ** interface was added.  This interface is retained for backwards
 ** compatibility and as a convenience for applications that need to manually
 ** start a callback but which do not need the full power (and corresponding
 ** complication) of [sqlite3_wal_checkpoint_v2()].
 */
 SQLITE_API int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb);
 
 /*
 ** CAPI3REF: Checkpoint a database
 ** METHOD: sqlite3
 **
 ** ^(The sqlite3_wal_checkpoint_v2(D,X,M,L,C) interface runs a checkpoint
 ** operation on database X of [database connection] D in mode M.  Status
 ** information is written back into integers pointed to by L and C.)^
 ** ^(The M parameter must be a valid [checkpoint mode]:)^
 **
 ** <dl>
 ** <dt>SQLITE_CHECKPOINT_PASSIVE<dd>
 **   ^Checkpoint as many frames as possible without waiting for any database 
 **   readers or writers to finish, then sync the database file if all frames 
 **   in the log were checkpointed. ^The [busy-handler callback]
 **   is never invoked in the SQLITE_CHECKPOINT_PASSIVE mode.  
 **   ^On the other hand, passive mode might leave the checkpoint unfinished
 **   if there are concurrent readers or writers.
 **
 ** <dt>SQLITE_CHECKPOINT_FULL<dd>
 **   ^This mode blocks (it invokes the
 **   [sqlite3_busy_handler|busy-handler callback]) until there is no
 **   database writer and all readers are reading from the most recent database
 **   snapshot. ^It then checkpoints all frames in the log file and syncs the
 **   database file. ^This mode blocks new database writers while it is pending,
 **   but new database readers are allowed to continue unimpeded.
 **
 ** <dt>SQLITE_CHECKPOINT_RESTART<dd>
 **   ^This mode works the same way as SQLITE_CHECKPOINT_FULL with the addition
 **   that after checkpointing the log file it blocks (calls the 
 **   [busy-handler callback])
 **   until all readers are reading from the database file only. ^This ensures 
 **   that the next writer will restart the log file from the beginning.
 **   ^Like SQLITE_CHECKPOINT_FULL, this mode blocks new
 **   database writer attempts while it is pending, but does not impede readers.
 **
 ** <dt>SQLITE_CHECKPOINT_TRUNCATE<dd>
 **   ^This mode works the same way as SQLITE_CHECKPOINT_RESTART with the
 **   addition that it also truncates the log file to zero bytes just prior
 **   to a successful return.
 ** </dl>
 **
 ** ^If pnLog is not NULL, then *pnLog is set to the total number of frames in
 ** the log file or to -1 if the checkpoint could not run because
 ** of an error or because the database is not in [WAL mode]. ^If pnCkpt is not
 ** NULL,then *pnCkpt is set to the total number of checkpointed frames in the
 ** log file (including any that were already checkpointed before the function
 ** was called) or to -1 if the checkpoint could not run due to an error or
 ** because the database is not in WAL mode. ^Note that upon successful
 ** completion of an SQLITE_CHECKPOINT_TRUNCATE, the log file will have been
 ** truncated to zero bytes and so both *pnLog and *pnCkpt will be set to zero.
 **
 ** ^All calls obtain an exclusive "checkpoint" lock on the database file. ^If
 ** any other process is running a checkpoint operation at the same time, the 
 ** lock cannot be obtained and SQLITE_BUSY is returned. ^Even if there is a 
 ** busy-handler configured, it will not be invoked in this case.
 **
 ** ^The SQLITE_CHECKPOINT_FULL, RESTART and TRUNCATE modes also obtain the 
 ** exclusive "writer" lock on the database file. ^If the writer lock cannot be
 ** obtained immediately, and a busy-handler is configured, it is invoked and
 ** the writer lock retried until either the busy-handler returns 0 or the lock
 ** is successfully obtained. ^The busy-handler is also invoked while waiting for
 ** database readers as described above. ^If the busy-handler returns 0 before
 ** the writer lock is obtained or while waiting for database readers, the
 ** checkpoint operation proceeds from that point in the same way as 
 ** SQLITE_CHECKPOINT_PASSIVE - checkpointing as many frames as possible 
 ** without blocking any further. ^SQLITE_BUSY is returned in this case.
 **
 ** ^If parameter zDb is NULL or points to a zero length string, then the
 ** specified operation is attempted on all WAL databases [attached] to 
 ** [database connection] db.  In this case the
 ** values written to output parameters *pnLog and *pnCkpt are undefined. ^If 
 ** an SQLITE_BUSY error is encountered when processing one or more of the 
 ** attached WAL databases, the operation is still attempted on any remaining 
 ** attached databases and SQLITE_BUSY is returned at the end. ^If any other 
 ** error occurs while processing an attached database, processing is abandoned 
 ** and the error code is returned to the caller immediately. ^If no error 
 ** (SQLITE_BUSY or otherwise) is encountered while processing the attached 
 ** databases, SQLITE_OK is returned.
 **
 ** ^If database zDb is the name of an attached database that is not in WAL
 ** mode, SQLITE_OK is returned and both *pnLog and *pnCkpt set to -1. ^If
 ** zDb is not NULL (or a zero length string) and is not the name of any
 ** attached database, SQLITE_ERROR is returned to the caller.
 **
 ** ^Unless it returns SQLITE_MISUSE,
 ** the sqlite3_wal_checkpoint_v2() interface
 ** sets the error information that is queried by
 ** [sqlite3_errcode()] and [sqlite3_errmsg()].
 **
 ** ^The [PRAGMA wal_checkpoint] command can be used to invoke this interface
 ** from SQL.
 */
 SQLITE_API int sqlite3_wal_checkpoint_v2(
   sqlite3 *db,                    /* Database handle */
   const char *zDb,                /* Name of attached database (or NULL) */
   int eMode,                      /* SQLITE_CHECKPOINT_* value */
   int *pnLog,                     /* OUT: Size of WAL log in frames */
   int *pnCkpt                     /* OUT: Total number of frames checkpointed */
 );
 
 /*
 ** CAPI3REF: Checkpoint Mode Values
 ** KEYWORDS: {checkpoint mode}
 **
 ** These constants define all valid values for the "checkpoint mode" passed
 ** as the third parameter to the [sqlite3_wal_checkpoint_v2()] interface.
 ** See the [sqlite3_wal_checkpoint_v2()] documentation for details on the
 ** meaning of each of these checkpoint modes.
 */
 #define SQLITE_CHECKPOINT_PASSIVE  0  /* Do as much as possible w/o blocking */
 #define SQLITE_CHECKPOINT_FULL     1  /* Wait for writers, then checkpoint */
 #define SQLITE_CHECKPOINT_RESTART  2  /* Like FULL but wait for for readers */
 #define SQLITE_CHECKPOINT_TRUNCATE 3  /* Like RESTART but also truncate WAL */
 
 /*
 ** CAPI3REF: Virtual Table Interface Configuration
 **
 ** This function may be called by either the [xConnect] or [xCreate] method
 ** of a [virtual table] implementation to configure
 ** various facets of the virtual table interface.
 **
 ** If this interface is invoked outside the context of an xConnect or
 ** xCreate virtual table method then the behavior is undefined.
 **
 ** At present, there is only one option that may be configured using
 ** this function. (See [SQLITE_VTAB_CONSTRAINT_SUPPORT].)  Further options
 ** may be added in the future.
 */
 SQLITE_API int sqlite3_vtab_config(sqlite3*, int op, ...);
 
 /*
 ** CAPI3REF: Virtual Table Configuration Options
 **
 ** These macros define the various options to the
 ** [sqlite3_vtab_config()] interface that [virtual table] implementations
 ** can use to customize and optimize their behavior.
 **
 ** <dl>
 ** <dt>SQLITE_VTAB_CONSTRAINT_SUPPORT
 ** <dd>Calls of the form
 ** [sqlite3_vtab_config](db,SQLITE_VTAB_CONSTRAINT_SUPPORT,X) are supported,
 ** where X is an integer.  If X is zero, then the [virtual table] whose
 ** [xCreate] or [xConnect] method invoked [sqlite3_vtab_config()] does not
 ** support constraints.  In this configuration (which is the default) if
 ** a call to the [xUpdate] method returns [SQLITE_CONSTRAINT], then the entire
 ** statement is rolled back as if [ON CONFLICT | OR ABORT] had been
 ** specified as part of the users SQL statement, regardless of the actual
 ** ON CONFLICT mode specified.
 **
 ** If X is non-zero, then the virtual table implementation guarantees
 ** that if [xUpdate] returns [SQLITE_CONSTRAINT], it will do so before
 ** any modifications to internal or persistent data structures have been made.
 ** If the [ON CONFLICT] mode is ABORT, FAIL, IGNORE or ROLLBACK, SQLite 
 ** is able to roll back a statement or database transaction, and abandon
 ** or continue processing the current SQL statement as appropriate. 
 ** If the ON CONFLICT mode is REPLACE and the [xUpdate] method returns
 ** [SQLITE_CONSTRAINT], SQLite handles this as if the ON CONFLICT mode
 ** had been ABORT.
 **
 ** Virtual table implementations that are required to handle OR REPLACE
 ** must do so within the [xUpdate] method. If a call to the 
 ** [sqlite3_vtab_on_conflict()] function indicates that the current ON 
 ** CONFLICT policy is REPLACE, the virtual table implementation should 
 ** silently replace the appropriate rows within the xUpdate callback and
 ** return SQLITE_OK. Or, if this is not possible, it may return
 ** SQLITE_CONSTRAINT, in which case SQLite falls back to OR ABORT 
 ** constraint handling.
 ** </dl>
 */
 #define SQLITE_VTAB_CONSTRAINT_SUPPORT 1
 
 /*
 ** CAPI3REF: Determine The Virtual Table Conflict Policy
 **
 ** This function may only be called from within a call to the [xUpdate] method
 ** of a [virtual table] implementation for an INSERT or UPDATE operation. ^The
 ** value returned is one of [SQLITE_ROLLBACK], [SQLITE_IGNORE], [SQLITE_FAIL],
 ** [SQLITE_ABORT], or [SQLITE_REPLACE], according to the [ON CONFLICT] mode
 ** of the SQL statement that triggered the call to the [xUpdate] method of the
 ** [virtual table].
 */
 SQLITE_API int sqlite3_vtab_on_conflict(sqlite3 *);
 
 /*
 ** CAPI3REF: Determine If Virtual Table Column Access Is For UPDATE
 **
 ** If the sqlite3_vtab_nochange(X) routine is called within the [xColumn]
 ** method of a [virtual table], then it returns true if and only if the
 ** column is being fetched as part of an UPDATE operation during which the
 ** column value will not change.  Applications might use this to substitute
 ** a lighter-weight value to return that the corresponding [xUpdate] method
 ** understands as a "no-change" value.
 **
 ** If the [xColumn] method calls sqlite3_vtab_nochange() and finds that
 ** the column is not changed by the UPDATE statement, they the xColumn
 ** method can optionally return without setting a result, without calling
 ** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
 ** In that case, [sqlite3_value_nochange(X)] will return true for the
 ** same column in the [xUpdate] method.
 */
 SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
 
 /*
 ** CAPI3REF: Determine The Collation For a Virtual Table Constraint
 **
 ** This function may only be called from within a call to the [xBestIndex]
 ** method of a [virtual table]. 
 **
 ** The first argument must be the sqlite3_index_info object that is the
 ** first parameter to the xBestIndex() method. The second argument must be
 ** an index into the aConstraint[] array belonging to the sqlite3_index_info
 ** structure passed to xBestIndex. This function returns a pointer to a buffer 
 ** containing the name of the collation sequence for the corresponding
 ** constraint.
 */
 SQLITE_API SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
 
 /*
 ** CAPI3REF: Conflict resolution modes
 ** KEYWORDS: {conflict resolution mode}
 **
 ** These constants are returned by [sqlite3_vtab_on_conflict()] to
 ** inform a [virtual table] implementation what the [ON CONFLICT] mode
 ** is for the SQL statement being evaluated.
 **
 ** Note that the [SQLITE_IGNORE] constant is also used as a potential
 ** return value from the [sqlite3_set_authorizer()] callback and that
 ** [SQLITE_ABORT] is also a [result code].
 */
 #define SQLITE_ROLLBACK 1
 /* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
 #define SQLITE_FAIL     3
 /* #define SQLITE_ABORT 4  // Also an error code */
 #define SQLITE_REPLACE  5
 
 /*
 ** CAPI3REF: Prepared Statement Scan Status Opcodes
 ** KEYWORDS: {scanstatus options}
 **
 ** The following constants can be used for the T parameter to the
 ** [sqlite3_stmt_scanstatus(S,X,T,V)] interface.  Each constant designates a
 ** different metric for sqlite3_stmt_scanstatus() to return.
 **
 ** When the value returned to V is a string, space to hold that string is
 ** managed by the prepared statement S and will be automatically freed when
 ** S is finalized.
 **
 ** <dl>
 ** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
 ** set to the total number of times that the X-th loop has run.</dd>
 **
 ** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
 ** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
 ** to the total number of rows examined by all iterations of the X-th loop.</dd>
 **
 ** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
 ** <dd>^The "double" variable pointed to by the T parameter will be set to the
 ** query planner's estimate for the average number of rows output from each
 ** iteration of the X-th loop.  If the query planner's estimates was accurate,
 ** then this value will approximate the quotient NVISIT/NLOOP and the
 ** product of this value for all prior loops with the same SELECTID will
 ** be the NLOOP value for the current loop.
 **
 ** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
 ** to a zero-terminated UTF-8 string containing the name of the index or table
 ** used for the X-th loop.
 **
 ** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
 ** <dd>^The "const char *" variable pointed to by the T parameter will be set
 ** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
 ** description for the X-th loop.
 **
 ** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
 ** <dd>^The "int" variable pointed to by the T parameter will be set to the
 ** "select-id" for the X-th loop.  The select-id identifies which query or
 ** subquery the loop is part of.  The main query has a select-id of zero.
 ** The select-id is the same value as is output in the first column
 ** of an [EXPLAIN QUERY PLAN] query.
 ** </dl>
 */
 #define SQLITE_SCANSTAT_NLOOP    0
 #define SQLITE_SCANSTAT_NVISIT   1
 #define SQLITE_SCANSTAT_EST      2
 #define SQLITE_SCANSTAT_NAME     3
 #define SQLITE_SCANSTAT_EXPLAIN  4
 #define SQLITE_SCANSTAT_SELECTID 5
 
 /*
 ** CAPI3REF: Prepared Statement Scan Status
 ** METHOD: sqlite3_stmt
 **
 ** This interface returns information about the predicted and measured
 ** performance for pStmt.  Advanced applications can use this
 ** interface to compare the predicted and the measured performance and
 ** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
 **
 ** Since this interface is expected to be rarely used, it is only
 ** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
 ** compile-time option.
 **
 ** The "iScanStatusOp" parameter determines which status information to return.
 ** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
 ** of this interface is undefined.
 ** ^The requested measurement is written into a variable pointed to by
 ** the "pOut" parameter.
 ** Parameter "idx" identifies the specific loop to retrieve statistics for.
 ** Loops are numbered starting from zero. ^If idx is out of range - less than
 ** zero or greater than or equal to the total number of loops used to implement
 ** the statement - a non-zero value is returned and the variable that pOut
 ** points to is unchanged.
 **
 ** ^Statistics might not be available for all loops in all statements. ^In cases
 ** where there exist loops with no available statistics, this function behaves
 ** as if the loop did not exist - it returns non-zero and leave the variable
 ** that pOut points to unchanged.
 **
 ** See also: [sqlite3_stmt_scanstatus_reset()]
 */
 SQLITE_API int sqlite3_stmt_scanstatus(
   sqlite3_stmt *pStmt,      /* Prepared statement for which info desired */
   int idx,                  /* Index of loop to report on */
   int iScanStatusOp,        /* Information desired.  SQLITE_SCANSTAT_* */
   void *pOut                /* Result written here */
 );     
 
 /*
 ** CAPI3REF: Zero Scan-Status Counters
 ** METHOD: sqlite3_stmt
 **
 ** ^Zero all [sqlite3_stmt_scanstatus()] related event counters.
 **
 ** This API is only available if the library is built with pre-processor
 ** symbol [SQLITE_ENABLE_STMT_SCANSTATUS] defined.
 */
 SQLITE_API void sqlite3_stmt_scanstatus_reset(sqlite3_stmt*);
 
 /*
 ** CAPI3REF: Flush caches to disk mid-transaction
 **
 ** ^If a write-transaction is open on [database connection] D when the
 ** [sqlite3_db_cacheflush(D)] interface invoked, any dirty
 ** pages in the pager-cache that are not currently in use are written out 
 ** to disk. A dirty page may be in use if a database cursor created by an
 ** active SQL statement is reading from it, or if it is page 1 of a database
 ** file (page 1 is always "in use").  ^The [sqlite3_db_cacheflush(D)]
 ** interface flushes caches for all schemas - "main", "temp", and
 ** any [attached] databases.
 **
 ** ^If this function needs to obtain extra database locks before dirty pages 
 ** can be flushed to disk, it does so. ^If those locks cannot be obtained 
 ** immediately and there is a busy-handler callback configured, it is invoked
 ** in the usual manner. ^If the required lock still cannot be obtained, then
 ** the database is skipped and an attempt made to flush any dirty pages
 ** belonging to the next (if any) database. ^If any databases are skipped
 ** because locks cannot be obtained, but no other error occurs, this
 ** function returns SQLITE_BUSY.
 **
 ** ^If any other error occurs while flushing dirty pages to disk (for
 ** example an IO error or out-of-memory condition), then processing is
 ** abandoned and an SQLite [error code] is returned to the caller immediately.
 **
 ** ^Otherwise, if no error occurs, [sqlite3_db_cacheflush()] returns SQLITE_OK.
 **
 ** ^This function does not set the database handle error code or message
 ** returned by the [sqlite3_errcode()] and [sqlite3_errmsg()] functions.
 */
 SQLITE_API int sqlite3_db_cacheflush(sqlite3*);
 
 /*
 ** CAPI3REF: The pre-update hook.
 **
 ** ^These interfaces are only available if SQLite is compiled using the
 ** [SQLITE_ENABLE_PREUPDATE_HOOK] compile-time option.
 **
 ** ^The [sqlite3_preupdate_hook()] interface registers a callback function
 ** that is invoked prior to each [INSERT], [UPDATE], and [DELETE] operation
 ** on a database table.
 ** ^At most one preupdate hook may be registered at a time on a single
 ** [database connection]; each call to [sqlite3_preupdate_hook()] overrides
 ** the previous setting.
 ** ^The preupdate hook is disabled by invoking [sqlite3_preupdate_hook()]
 ** with a NULL pointer as the second parameter.
 ** ^The third parameter to [sqlite3_preupdate_hook()] is passed through as
 ** the first parameter to callbacks.
 **
 ** ^The preupdate hook only fires for changes to real database tables; the
 ** preupdate hook is not invoked for changes to [virtual tables] or to
 ** system tables like sqlite_master or sqlite_stat1.
 **
 ** ^The second parameter to the preupdate callback is a pointer to
 ** the [database connection] that registered the preupdate hook.
 ** ^The third parameter to the preupdate callback is one of the constants
 ** [SQLITE_INSERT], [SQLITE_DELETE], or [SQLITE_UPDATE] to identify the
 ** kind of update operation that is about to occur.
 ** ^(The fourth parameter to the preupdate callback is the name of the
 ** database within the database connection that is being modified.  This
 ** will be "main" for the main database or "temp" for TEMP tables or 
 ** the name given after the AS keyword in the [ATTACH] statement for attached
 ** databases.)^
 ** ^The fifth parameter to the preupdate callback is the name of the
 ** table that is being modified.
 **
 ** For an UPDATE or DELETE operation on a [rowid table], the sixth
 ** parameter passed to the preupdate callback is the initial [rowid] of the 
 ** row being modified or deleted. For an INSERT operation on a rowid table,
 ** or any operation on a WITHOUT ROWID table, the value of the sixth 
 ** parameter is undefined. For an INSERT or UPDATE on a rowid table the
 ** seventh parameter is the final rowid value of the row being inserted
 ** or updated. The value of the seventh parameter passed to the callback
 ** function is not defined for operations on WITHOUT ROWID tables, or for
 ** INSERT operations on rowid tables.
 **
 ** The [sqlite3_preupdate_old()], [sqlite3_preupdate_new()],
 ** [sqlite3_preupdate_count()], and [sqlite3_preupdate_depth()] interfaces
 ** provide additional information about a preupdate event. These routines
 ** may only be called from within a preupdate callback.  Invoking any of
 ** these routines from outside of a preupdate callback or with a
 ** [database connection] pointer that is different from the one supplied
 ** to the preupdate callback results in undefined and probably undesirable
 ** behavior.
 **
 ** ^The [sqlite3_preupdate_count(D)] interface returns the number of columns
 ** in the row that is being inserted, updated, or deleted.
 **
 ** ^The [sqlite3_preupdate_old(D,N,P)] interface writes into P a pointer to
 ** a [protected sqlite3_value] that contains the value of the Nth column of
 ** the table row before it is updated.  The N parameter must be between 0
 ** and one less than the number of columns or the behavior will be
 ** undefined. This must only be used within SQLITE_UPDATE and SQLITE_DELETE
 ** preupdate callbacks; if it is used by an SQLITE_INSERT callback then the
 ** behavior is undefined.  The [sqlite3_value] that P points to
 ** will be destroyed when the preupdate callback returns.
 **
 ** ^The [sqlite3_preupdate_new(D,N,P)] interface writes into P a pointer to
 ** a [protected sqlite3_value] that contains the value of the Nth column of
 ** the table row after it is updated.  The N parameter must be between 0
 ** and one less than the number of columns or the behavior will be
 ** undefined. This must only be used within SQLITE_INSERT and SQLITE_UPDATE
 ** preupdate callbacks; if it is used by an SQLITE_DELETE callback then the
 ** behavior is undefined.  The [sqlite3_value] that P points to
 ** will be destroyed when the preupdate callback returns.
 **
 ** ^The [sqlite3_preupdate_depth(D)] interface returns 0 if the preupdate
 ** callback was invoked as a result of a direct insert, update, or delete
 ** operation; or 1 for inserts, updates, or deletes invoked by top-level 
 ** triggers; or 2 for changes resulting from triggers called by top-level
 ** triggers; and so forth.
 **
 ** See also:  [sqlite3_update_hook()]
 */
 #if defined(SQLITE_ENABLE_PREUPDATE_HOOK)
 SQLITE_API void *sqlite3_preupdate_hook(
   sqlite3 *db,
   void(*xPreUpdate)(
     void *pCtx,                   /* Copy of third arg to preupdate_hook() */
     sqlite3 *db,                  /* Database handle */
     int op,                       /* SQLITE_UPDATE, DELETE or INSERT */
     char const *zDb,              /* Database name */
     char const *zName,            /* Table name */
     sqlite3_int64 iKey1,          /* Rowid of row about to be deleted/updated */
     sqlite3_int64 iKey2           /* New rowid value (for a rowid UPDATE) */
   ),
   void*
 );
 SQLITE_API int sqlite3_preupdate_old(sqlite3 *, int, sqlite3_value **);
 SQLITE_API int sqlite3_preupdate_count(sqlite3 *);
 SQLITE_API int sqlite3_preupdate_depth(sqlite3 *);
 SQLITE_API int sqlite3_preupdate_new(sqlite3 *, int, sqlite3_value **);
 #endif
 
 /*
 ** CAPI3REF: Low-level system error code
 **
 ** ^Attempt to return the underlying operating system error code or error
 ** number that caused the most recent I/O error or failure to open a file.
 ** The return value is OS-dependent.  For example, on unix systems, after
 ** [sqlite3_open_v2()] returns [SQLITE_CANTOPEN], this interface could be
 ** called to get back the underlying "errno" that caused the problem, such
 ** as ENOSPC, EAUTH, EISDIR, and so forth.  
 */
 SQLITE_API int sqlite3_system_errno(sqlite3*);
 
 /*
 ** CAPI3REF: Database Snapshot
 ** KEYWORDS: {snapshot} {sqlite3_snapshot}
 ** EXPERIMENTAL
 **
 ** An instance of the snapshot object records the state of a [WAL mode]
 ** database for some specific point in history.
 **
 ** In [WAL mode], multiple [database connections] that are open on the
 ** same database file can each be reading a different historical version
 ** of the database file.  When a [database connection] begins a read
 ** transaction, that connection sees an unchanging copy of the database
 ** as it existed for the point in time when the transaction first started.
 ** Subsequent changes to the database from other connections are not seen
 ** by the reader until a new read transaction is started.
 **
 ** The sqlite3_snapshot object records state information about an historical
 ** version of the database file so that it is possible to later open a new read
 ** transaction that sees that historical version of the database rather than
 ** the most recent version.
 **
 ** The constructor for this object is [sqlite3_snapshot_get()].  The
 ** [sqlite3_snapshot_open()] method causes a fresh read transaction to refer
 ** to an historical snapshot (if possible).  The destructor for 
 ** sqlite3_snapshot objects is [sqlite3_snapshot_free()].
 */
 typedef struct sqlite3_snapshot {
   unsigned char hidden[48];
 } sqlite3_snapshot;
 
 /*
 ** CAPI3REF: Record A Database Snapshot
 ** EXPERIMENTAL
 **
 ** ^The [sqlite3_snapshot_get(D,S,P)] interface attempts to make a
 ** new [sqlite3_snapshot] object that records the current state of
 ** schema S in database connection D.  ^On success, the
 ** [sqlite3_snapshot_get(D,S,P)] interface writes a pointer to the newly
 ** created [sqlite3_snapshot] object into *P and returns SQLITE_OK.
 ** If there is not already a read-transaction open on schema S when
 ** this function is called, one is opened automatically. 
 **
 ** The following must be true for this function to succeed. If any of
 ** the following statements are false when sqlite3_snapshot_get() is
 ** called, SQLITE_ERROR is returned. The final value of *P is undefined
 ** in this case. 
 **
 ** <ul>
 **   <li> The database handle must be in [autocommit mode].
 **
 **   <li> Schema S of [database connection] D must be a [WAL mode] database.
 **
 **   <li> There must not be a write transaction open on schema S of database
 **        connection D.
 **
 **   <li> One or more transactions must have been written to the current wal
 **        file since it was created on disk (by any connection). This means
 **        that a snapshot cannot be taken on a wal mode database with no wal 
 **        file immediately after it is first opened. At least one transaction
 **        must be written to it first.
 ** </ul>
 **
 ** This function may also return SQLITE_NOMEM.  If it is called with the
 ** database handle in autocommit mode but fails for some other reason, 
 ** whether or not a read transaction is opened on schema S is undefined.
 **
 ** The [sqlite3_snapshot] object returned from a successful call to
 ** [sqlite3_snapshot_get()] must be freed using [sqlite3_snapshot_free()]
 ** to avoid a memory leak.
 **
 ** The [sqlite3_snapshot_get()] interface is only available when the
 ** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
 */
 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_get(
   sqlite3 *db,
   const char *zSchema,
   sqlite3_snapshot **ppSnapshot
 );
 
 /*
 ** CAPI3REF: Start a read transaction on an historical snapshot
 ** EXPERIMENTAL
 **
 ** ^The [sqlite3_snapshot_open(D,S,P)] interface starts a
 ** read transaction for schema S of
 ** [database connection] D such that the read transaction
 ** refers to historical [snapshot] P, rather than the most
 ** recent change to the database.
 ** ^The [sqlite3_snapshot_open()] interface returns SQLITE_OK on success
 ** or an appropriate [error code] if it fails.
 **
 ** ^In order to succeed, a call to [sqlite3_snapshot_open(D,S,P)] must be
 ** the first operation following the [BEGIN] that takes the schema S
 ** out of [autocommit mode].
 ** ^In other words, schema S must not currently be in
 ** a transaction for [sqlite3_snapshot_open(D,S,P)] to work, but the
 ** database connection D must be out of [autocommit mode].
 ** ^A [snapshot] will fail to open if it has been overwritten by a
 ** [checkpoint].
 ** ^(A call to [sqlite3_snapshot_open(D,S,P)] will fail if the
 ** database connection D does not know that the database file for
 ** schema S is in [WAL mode].  A database connection might not know
 ** that the database file is in [WAL mode] if there has been no prior
 ** I/O on that database connection, or if the database entered [WAL mode] 
 ** after the most recent I/O on the database connection.)^
 ** (Hint: Run "[PRAGMA application_id]" against a newly opened
 ** database connection in order to make it ready to use snapshots.)
 **
 ** The [sqlite3_snapshot_open()] interface is only available when the
 ** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
 */
 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_open(
   sqlite3 *db,
   const char *zSchema,
   sqlite3_snapshot *pSnapshot
 );
 
 /*
 ** CAPI3REF: Destroy a snapshot
 ** EXPERIMENTAL
 **
 ** ^The [sqlite3_snapshot_free(P)] interface destroys [sqlite3_snapshot] P.
 ** The application must eventually free every [sqlite3_snapshot] object
 ** using this routine to avoid a memory leak.
 **
 ** The [sqlite3_snapshot_free()] interface is only available when the
 ** SQLITE_ENABLE_SNAPSHOT compile-time option is used.
 */
 SQLITE_API SQLITE_EXPERIMENTAL void sqlite3_snapshot_free(sqlite3_snapshot*);
 
 /*
 ** CAPI3REF: Compare the ages of two snapshot handles.
 ** EXPERIMENTAL
 **
 ** The sqlite3_snapshot_cmp(P1, P2) interface is used to compare the ages
 ** of two valid snapshot handles. 
 **
 ** If the two snapshot handles are not associated with the same database 
 ** file, the result of the comparison is undefined. 
 **
 ** Additionally, the result of the comparison is only valid if both of the
 ** snapshot handles were obtained by calling sqlite3_snapshot_get() since the
 ** last time the wal file was deleted. The wal file is deleted when the
 ** database is changed back to rollback mode or when the number of database
 ** clients drops to zero. If either snapshot handle was obtained before the 
 ** wal file was last deleted, the value returned by this function 
 ** is undefined.
 **
 ** Otherwise, this API returns a negative value if P1 refers to an older
 ** snapshot than P2, zero if the two handles refer to the same database
 ** snapshot, and a positive value if P1 is a newer snapshot than P2.
 */
 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_cmp(
   sqlite3_snapshot *p1,
   sqlite3_snapshot *p2
 );
 
 /*
 ** CAPI3REF: Recover snapshots from a wal file
 ** EXPERIMENTAL
 **
 ** If all connections disconnect from a database file but do not perform
 ** a checkpoint, the existing wal file is opened along with the database
 ** file the next time the database is opened. At this point it is only
 ** possible to successfully call sqlite3_snapshot_open() to open the most
 ** recent snapshot of the database (the one at the head of the wal file),
 ** even though the wal file may contain other valid snapshots for which
 ** clients have sqlite3_snapshot handles.
 **
 ** This function attempts to scan the wal file associated with database zDb
 ** of database handle db and make all valid snapshots available to
 ** sqlite3_snapshot_open(). It is an error if there is already a read
 ** transaction open on the database, or if the database is not a wal mode
 ** database.
 **
 ** SQLITE_OK is returned if successful, or an SQLite error code otherwise.
 */
 SQLITE_API SQLITE_EXPERIMENTAL int sqlite3_snapshot_recover(sqlite3 *db, const char *zDb);
 
 /*
 ** Undo the hack that converts floating point types to integer for
 ** builds on processors without floating point support.
 */
 #ifdef SQLITE_OMIT_FLOATING_POINT
 # undef double
 #endif
 
 #ifdef __cplusplus
 }  /* End of the 'extern "C"' block */
 #endif
 #endif /* SQLITE3_H */
 
 /******** Begin file sqlite3rtree.h *********/
 /*
 ** 2010 August 30
 **
 ** The author disclaims copyright to this source code.  In place of
 ** a legal notice, here is a blessing:
 **
 **    May you do good and not evil.
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 *************************************************************************
 */
 
 #ifndef _SQLITE3RTREE_H_
 #define _SQLITE3RTREE_H_
 
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 typedef struct sqlite3_rtree_geometry sqlite3_rtree_geometry;
 typedef struct sqlite3_rtree_query_info sqlite3_rtree_query_info;
 
 /* The double-precision datatype used by RTree depends on the
 ** SQLITE_RTREE_INT_ONLY compile-time option.
 */
 #ifdef SQLITE_RTREE_INT_ONLY
   typedef sqlite3_int64 sqlite3_rtree_dbl;
 #else
   typedef double sqlite3_rtree_dbl;
 #endif
 
 /*
 ** Register a geometry callback named zGeom that can be used as part of an
 ** R-Tree geometry query as follows:
 **
 **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zGeom(... params ...)
 */
 SQLITE_API int sqlite3_rtree_geometry_callback(
   sqlite3 *db,
   const char *zGeom,
   int (*xGeom)(sqlite3_rtree_geometry*, int, sqlite3_rtree_dbl*,int*),
   void *pContext
 );
 
 
 /*
 ** A pointer to a structure of the following type is passed as the first
 ** argument to callbacks registered using rtree_geometry_callback().
 */
 struct sqlite3_rtree_geometry {
   void *pContext;                 /* Copy of pContext passed to s_r_g_c() */
   int nParam;                     /* Size of array aParam[] */
   sqlite3_rtree_dbl *aParam;      /* Parameters passed to SQL geom function */
   void *pUser;                    /* Callback implementation user data */
   void (*xDelUser)(void *);       /* Called by SQLite to clean up pUser */
 };
 
 /*
 ** Register a 2nd-generation geometry callback named zScore that can be 
 ** used as part of an R-Tree geometry query as follows:
 **
 **   SELECT ... FROM <rtree> WHERE <rtree col> MATCH $zQueryFunc(... params ...)
 */
 SQLITE_API int sqlite3_rtree_query_callback(
   sqlite3 *db,
   const char *zQueryFunc,
   int (*xQueryFunc)(sqlite3_rtree_query_info*),
   void *pContext,
   void (*xDestructor)(void*)
 );
 
 
 /*
 ** A pointer to a structure of the following type is passed as the 
 ** argument to scored geometry callback registered using
 ** sqlite3_rtree_query_callback().
 **
 ** Note that the first 5 fields of this structure are identical to
 ** sqlite3_rtree_geometry.  This structure is a subclass of
 ** sqlite3_rtree_geometry.
 */
 struct sqlite3_rtree_query_info {
   void *pContext;                   /* pContext from when function registered */
   int nParam;                       /* Number of function parameters */
   sqlite3_rtree_dbl *aParam;        /* value of function parameters */
   void *pUser;                      /* callback can use this, if desired */
   void (*xDelUser)(void*);          /* function to free pUser */
   sqlite3_rtree_dbl *aCoord;        /* Coordinates of node or entry to check */
   unsigned int *anQueue;            /* Number of pending entries in the queue */
   int nCoord;                       /* Number of coordinates */
   int iLevel;                       /* Level of current node or entry */
   int mxLevel;                      /* The largest iLevel value in the tree */
   sqlite3_int64 iRowid;             /* Rowid for current entry */
   sqlite3_rtree_dbl rParentScore;   /* Score of parent node */
   int eParentWithin;                /* Visibility of parent node */
   int eWithin;                      /* OUT: Visiblity */
   sqlite3_rtree_dbl rScore;         /* OUT: Write the score here */
   /* The following fields are only available in 3.8.11 and later */
   sqlite3_value **apSqlParam;       /* Original SQL values of parameters */
 };
 
 /*
 ** Allowed values for sqlite3_rtree_query.eWithin and .eParentWithin.
 */
 #define NOT_WITHIN       0   /* Object completely outside of query region */
 #define PARTLY_WITHIN    1   /* Object partially overlaps query region */
 #define FULLY_WITHIN     2   /* Object fully contained within query region */
 
 
 #ifdef __cplusplus
 }  /* end of the 'extern "C"' block */
 #endif
 
 #endif  /* ifndef _SQLITE3RTREE_H_ */
 
 /******** End of sqlite3rtree.h *********/
 /******** Begin file sqlite3session.h *********/
 
 #if !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION)
 #define __SQLITESESSION_H_ 1
 
 /*
 ** Make sure we can call this stuff from C++.
 */
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 
 /*
 ** CAPI3REF: Session Object Handle
 */
 typedef struct sqlite3_session sqlite3_session;
 
 /*
 ** CAPI3REF: Changeset Iterator Handle
 */
 typedef struct sqlite3_changeset_iter sqlite3_changeset_iter;
 
 /*
 ** CAPI3REF: Create A New Session Object
 **
 ** Create a new session object attached to database handle db. If successful,
 ** a pointer to the new object is written to *ppSession and SQLITE_OK is
 ** returned. If an error occurs, *ppSession is set to NULL and an SQLite
 ** error code (e.g. SQLITE_NOMEM) is returned.
 **
 ** It is possible to create multiple session objects attached to a single
 ** database handle.
 **
 ** Session objects created using this function should be deleted using the
 ** [sqlite3session_delete()] function before the database handle that they
 ** are attached to is itself closed. If the database handle is closed before
 ** the session object is deleted, then the results of calling any session
 ** module function, including [sqlite3session_delete()] on the session object
 ** are undefined.
 **
 ** Because the session module uses the [sqlite3_preupdate_hook()] API, it
 ** is not possible for an application to register a pre-update hook on a
 ** database handle that has one or more session objects attached. Nor is
 ** it possible to create a session object attached to a database handle for
 ** which a pre-update hook is already defined. The results of attempting 
 ** either of these things are undefined.
 **
 ** The session object will be used to create changesets for tables in
 ** database zDb, where zDb is either "main", or "temp", or the name of an
 ** attached database. It is not an error if database zDb is not attached
 ** to the database when the session object is created.
 */
 SQLITE_API int sqlite3session_create(
   sqlite3 *db,                    /* Database handle */
   const char *zDb,                /* Name of db (e.g. "main") */
   sqlite3_session **ppSession     /* OUT: New session object */
 );
 
 /*
 ** CAPI3REF: Delete A Session Object
 **
 ** Delete a session object previously allocated using 
 ** [sqlite3session_create()]. Once a session object has been deleted, the
 ** results of attempting to use pSession with any other session module
 ** function are undefined.
 **
 ** Session objects must be deleted before the database handle to which they
 ** are attached is closed. Refer to the documentation for 
 ** [sqlite3session_create()] for details.
 */
 SQLITE_API void sqlite3session_delete(sqlite3_session *pSession);
 
 
 /*
 ** CAPI3REF: Enable Or Disable A Session Object
 **
 ** Enable or disable the recording of changes by a session object. When
 ** enabled, a session object records changes made to the database. When
 ** disabled - it does not. A newly created session object is enabled.
 ** Refer to the documentation for [sqlite3session_changeset()] for further
 ** details regarding how enabling and disabling a session object affects
 ** the eventual changesets.
 **
 ** Passing zero to this function disables the session. Passing a value
 ** greater than zero enables it. Passing a value less than zero is a 
 ** no-op, and may be used to query the current state of the session.
 **
 ** The return value indicates the final state of the session object: 0 if 
 ** the session is disabled, or 1 if it is enabled.
 */
 SQLITE_API int sqlite3session_enable(sqlite3_session *pSession, int bEnable);
 
 /*
 ** CAPI3REF: Set Or Clear the Indirect Change Flag
 **
 ** Each change recorded by a session object is marked as either direct or
 ** indirect. A change is marked as indirect if either:
 **
 ** <ul>
 **   <li> The session object "indirect" flag is set when the change is
 **        made, or
 **   <li> The change is made by an SQL trigger or foreign key action 
 **        instead of directly as a result of a users SQL statement.
 ** </ul>
 **
 ** If a single row is affected by more than one operation within a session,
 ** then the change is considered indirect if all operations meet the criteria
 ** for an indirect change above, or direct otherwise.
 **
 ** This function is used to set, clear or query the session object indirect
 ** flag.  If the second argument passed to this function is zero, then the
 ** indirect flag is cleared. If it is greater than zero, the indirect flag
 ** is set. Passing a value less than zero does not modify the current value
 ** of the indirect flag, and may be used to query the current state of the 
 ** indirect flag for the specified session object.
 **
 ** The return value indicates the final state of the indirect flag: 0 if 
 ** it is clear, or 1 if it is set.
 */
 SQLITE_API int sqlite3session_indirect(sqlite3_session *pSession, int bIndirect);
 
 /*
 ** CAPI3REF: Attach A Table To A Session Object
 **
 ** If argument zTab is not NULL, then it is the name of a table to attach
 ** to the session object passed as the first argument. All subsequent changes 
 ** made to the table while the session object is enabled will be recorded. See 
 ** documentation for [sqlite3session_changeset()] for further details.
 **
 ** Or, if argument zTab is NULL, then changes are recorded for all tables
 ** in the database. If additional tables are added to the database (by 
 ** executing "CREATE TABLE" statements) after this call is made, changes for 
 ** the new tables are also recorded.
 **
 ** Changes can only be recorded for tables that have a PRIMARY KEY explicitly
 ** defined as part of their CREATE TABLE statement. It does not matter if the 
 ** PRIMARY KEY is an "INTEGER PRIMARY KEY" (rowid alias) or not. The PRIMARY
 ** KEY may consist of a single column, or may be a composite key.
 ** 
 ** It is not an error if the named table does not exist in the database. Nor
 ** is it an error if the named table does not have a PRIMARY KEY. However,
 ** no changes will be recorded in either of these scenarios.
 **
 ** Changes are not recorded for individual rows that have NULL values stored
 ** in one or more of their PRIMARY KEY columns.
 **
 ** SQLITE_OK is returned if the call completes without error. Or, if an error 
 ** occurs, an SQLite error code (e.g. SQLITE_NOMEM) is returned.
 **
 ** <h3>Special sqlite_stat1 Handling</h3>
 **
 ** As of SQLite version 3.22.0, the "sqlite_stat1" table is an exception to 
 ** some of the rules above. In SQLite, the schema of sqlite_stat1 is:
 **  <pre>
 **  &nbsp;     CREATE TABLE sqlite_stat1(tbl,idx,stat)  
 **  </pre>
 **
 ** Even though sqlite_stat1 does not have a PRIMARY KEY, changes are 
 ** recorded for it as if the PRIMARY KEY is (tbl,idx). Additionally, changes 
 ** are recorded for rows for which (idx IS NULL) is true. However, for such
 ** rows a zero-length blob (SQL value X'') is stored in the changeset or
 ** patchset instead of a NULL value. This allows such changesets to be
 ** manipulated by legacy implementations of sqlite3changeset_invert(),
 ** concat() and similar.
 **
 ** The sqlite3changeset_apply() function automatically converts the 
 ** zero-length blob back to a NULL value when updating the sqlite_stat1
 ** table. However, if the application calls sqlite3changeset_new(),
 ** sqlite3changeset_old() or sqlite3changeset_conflict on a changeset 
 ** iterator directly (including on a changeset iterator passed to a
 ** conflict-handler callback) then the X'' value is returned. The application
 ** must translate X'' to NULL itself if required.
 **
 ** Legacy (older than 3.22.0) versions of the sessions module cannot capture
 ** changes made to the sqlite_stat1 table. Legacy versions of the
 ** sqlite3changeset_apply() function silently ignore any modifications to the
 ** sqlite_stat1 table that are part of a changeset or patchset.
 */
 SQLITE_API int sqlite3session_attach(
   sqlite3_session *pSession,      /* Session object */
   const char *zTab                /* Table name */
 );
 
 /*
 ** CAPI3REF: Set a table filter on a Session Object.
 **
 ** The second argument (xFilter) is the "filter callback". For changes to rows 
 ** in tables that are not attached to the Session object, the filter is called
 ** to determine whether changes to the table's rows should be tracked or not. 
 ** If xFilter returns 0, changes is not tracked. Note that once a table is 
 ** attached, xFilter will not be called again.
 */
 SQLITE_API void sqlite3session_table_filter(
   sqlite3_session *pSession,      /* Session object */
   int(*xFilter)(
     void *pCtx,                   /* Copy of third arg to _filter_table() */
     const char *zTab              /* Table name */
   ),
   void *pCtx                      /* First argument passed to xFilter */
 );
 
 /*
 ** CAPI3REF: Generate A Changeset From A Session Object
 **
 ** Obtain a changeset containing changes to the tables attached to the 
 ** session object passed as the first argument. If successful, 
 ** set *ppChangeset to point to a buffer containing the changeset 
 ** and *pnChangeset to the size of the changeset in bytes before returning
 ** SQLITE_OK. If an error occurs, set both *ppChangeset and *pnChangeset to
 ** zero and return an SQLite error code.
 **
 ** A changeset consists of zero or more INSERT, UPDATE and/or DELETE changes,
 ** each representing a change to a single row of an attached table. An INSERT
 ** change contains the values of each field of a new database row. A DELETE
 ** contains the original values of each field of a deleted database row. An
 ** UPDATE change contains the original values of each field of an updated
 ** database row along with the updated values for each updated non-primary-key
 ** column. It is not possible for an UPDATE change to represent a change that
 ** modifies the values of primary key columns. If such a change is made, it
 ** is represented in a changeset as a DELETE followed by an INSERT.
 **
 ** Changes are not recorded for rows that have NULL values stored in one or 
 ** more of their PRIMARY KEY columns. If such a row is inserted or deleted,
 ** no corresponding change is present in the changesets returned by this
 ** function. If an existing row with one or more NULL values stored in
 ** PRIMARY KEY columns is updated so that all PRIMARY KEY columns are non-NULL,
 ** only an INSERT is appears in the changeset. Similarly, if an existing row
 ** with non-NULL PRIMARY KEY values is updated so that one or more of its
 ** PRIMARY KEY columns are set to NULL, the resulting changeset contains a
 ** DELETE change only.
 **
 ** The contents of a changeset may be traversed using an iterator created
 ** using the [sqlite3changeset_start()] API. A changeset may be applied to
 ** a database with a compatible schema using the [sqlite3changeset_apply()]
 ** API.
 **
 ** Within a changeset generated by this function, all changes related to a
 ** single table are grouped together. In other words, when iterating through
 ** a changeset or when applying a changeset to a database, all changes related
 ** to a single table are processed before moving on to the next table. Tables
 ** are sorted in the same order in which they were attached (or auto-attached)
 ** to the sqlite3_session object. The order in which the changes related to
 ** a single table are stored is undefined.
 **
 ** Following a successful call to this function, it is the responsibility of
 ** the caller to eventually free the buffer that *ppChangeset points to using
 ** [sqlite3_free()].
 **
 ** <h3>Changeset Generation</h3>
 **
 ** Once a table has been attached to a session object, the session object
 ** records the primary key values of all new rows inserted into the table.
 ** It also records the original primary key and other column values of any
 ** deleted or updated rows. For each unique primary key value, data is only
 ** recorded once - the first time a row with said primary key is inserted,
 ** updated or deleted in the lifetime of the session.
 **
 ** There is one exception to the previous paragraph: when a row is inserted,
 ** updated or deleted, if one or more of its primary key columns contain a
 ** NULL value, no record of the change is made.
 **
 ** The session object therefore accumulates two types of records - those
 ** that consist of primary key values only (created when the user inserts
 ** a new record) and those that consist of the primary key values and the
 ** original values of other table columns (created when the users deletes
 ** or updates a record).
 **
 ** When this function is called, the requested changeset is created using
 ** both the accumulated records and the current contents of the database
 ** file. Specifically:
 **
 ** <ul>
 **   <li> For each record generated by an insert, the database is queried
 **        for a row with a matching primary key. If one is found, an INSERT
 **        change is added to the changeset. If no such row is found, no change 
 **        is added to the changeset.
 **
 **   <li> For each record generated by an update or delete, the database is 
 **        queried for a row with a matching primary key. If such a row is
 **        found and one or more of the non-primary key fields have been
 **        modified from their original values, an UPDATE change is added to 
 **        the changeset. Or, if no such row is found in the table, a DELETE 
 **        change is added to the changeset. If there is a row with a matching
 **        primary key in the database, but all fields contain their original
 **        values, no change is added to the changeset.
 ** </ul>
 **
 ** This means, amongst other things, that if a row is inserted and then later
 ** deleted while a session object is active, neither the insert nor the delete
 ** will be present in the changeset. Or if a row is deleted and then later a 
 ** row with the same primary key values inserted while a session object is
 ** active, the resulting changeset will contain an UPDATE change instead of
 ** a DELETE and an INSERT.
 **
 ** When a session object is disabled (see the [sqlite3session_enable()] API),
 ** it does not accumulate records when rows are inserted, updated or deleted.
 ** This may appear to have some counter-intuitive effects if a single row
 ** is written to more than once during a session. For example, if a row
 ** is inserted while a session object is enabled, then later deleted while 
 ** the same session object is disabled, no INSERT record will appear in the
 ** changeset, even though the delete took place while the session was disabled.
 ** Or, if one field of a row is updated while a session is disabled, and 
 ** another field of the same row is updated while the session is enabled, the
 ** resulting changeset will contain an UPDATE change that updates both fields.
 */
 SQLITE_API int sqlite3session_changeset(
   sqlite3_session *pSession,      /* Session object */
   int *pnChangeset,               /* OUT: Size of buffer at *ppChangeset */
   void **ppChangeset              /* OUT: Buffer containing changeset */
 );
 
 /*
 ** CAPI3REF: Load The Difference Between Tables Into A Session 
 **
 ** If it is not already attached to the session object passed as the first
 ** argument, this function attaches table zTbl in the same manner as the
 ** [sqlite3session_attach()] function. If zTbl does not exist, or if it
 ** does not have a primary key, this function is a no-op (but does not return
 ** an error).
 **
 ** Argument zFromDb must be the name of a database ("main", "temp" etc.)
 ** attached to the same database handle as the session object that contains 
 ** a table compatible with the table attached to the session by this function.
 ** A table is considered compatible if it:
 **
 ** <ul>
 **   <li> Has the same name,
 **   <li> Has the same set of columns declared in the same order, and
 **   <li> Has the same PRIMARY KEY definition.
 ** </ul>
 **
 ** If the tables are not compatible, SQLITE_SCHEMA is returned. If the tables
 ** are compatible but do not have any PRIMARY KEY columns, it is not an error
 ** but no changes are added to the session object. As with other session
 ** APIs, tables without PRIMARY KEYs are simply ignored.
 **
 ** This function adds a set of changes to the session object that could be
 ** used to update the table in database zFrom (call this the "from-table") 
 ** so that its content is the same as the table attached to the session 
 ** object (call this the "to-table"). Specifically:
 **
 ** <ul>
 **   <li> For each row (primary key) that exists in the to-table but not in 
 **     the from-table, an INSERT record is added to the session object.
 **
 **   <li> For each row (primary key) that exists in the to-table but not in 
 **     the from-table, a DELETE record is added to the session object.
 **
 **   <li> For each row (primary key) that exists in both tables, but features 
 **     different non-PK values in each, an UPDATE record is added to the
 **     session.  
 ** </ul>
 **
 ** To clarify, if this function is called and then a changeset constructed
 ** using [sqlite3session_changeset()], then after applying that changeset to 
 ** database zFrom the contents of the two compatible tables would be 
 ** identical.
 **
 ** It an error if database zFrom does not exist or does not contain the
 ** required compatible table.
 **
 ** If the operation successful, SQLITE_OK is returned. Otherwise, an SQLite
 ** error code. In this case, if argument pzErrMsg is not NULL, *pzErrMsg
 ** may be set to point to a buffer containing an English language error 
 ** message. It is the responsibility of the caller to free this buffer using
 ** sqlite3_free().
 */
 SQLITE_API int sqlite3session_diff(
   sqlite3_session *pSession,
   const char *zFromDb,
   const char *zTbl,
   char **pzErrMsg
 );
 
 
 /*
 ** CAPI3REF: Generate A Patchset From A Session Object
 **
 ** The differences between a patchset and a changeset are that:
 **
 ** <ul>
 **   <li> DELETE records consist of the primary key fields only. The 
 **        original values of other fields are omitted.
 **   <li> The original values of any modified fields are omitted from 
 **        UPDATE records.
 ** </ul>
 **
 ** A patchset blob may be used with up to date versions of all 
 ** sqlite3changeset_xxx API functions except for sqlite3changeset_invert(), 
 ** which returns SQLITE_CORRUPT if it is passed a patchset. Similarly,
 ** attempting to use a patchset blob with old versions of the
 ** sqlite3changeset_xxx APIs also provokes an SQLITE_CORRUPT error. 
 **
 ** Because the non-primary key "old.*" fields are omitted, no 
 ** SQLITE_CHANGESET_DATA conflicts can be detected or reported if a patchset
 ** is passed to the sqlite3changeset_apply() API. Other conflict types work
 ** in the same way as for changesets.
 **
 ** Changes within a patchset are ordered in the same way as for changesets
 ** generated by the sqlite3session_changeset() function (i.e. all changes for
 ** a single table are grouped together, tables appear in the order in which
 ** they were attached to the session object).
 */
 SQLITE_API int sqlite3session_patchset(
   sqlite3_session *pSession,      /* Session object */
   int *pnPatchset,                /* OUT: Size of buffer at *ppPatchset */
   void **ppPatchset               /* OUT: Buffer containing patchset */
 );
 
 /*
 ** CAPI3REF: Test if a changeset has recorded any changes.
 **
 ** Return non-zero if no changes to attached tables have been recorded by 
 ** the session object passed as the first argument. Otherwise, if one or 
 ** more changes have been recorded, return zero.
 **
 ** Even if this function returns zero, it is possible that calling
 ** [sqlite3session_changeset()] on the session handle may still return a
 ** changeset that contains no changes. This can happen when a row in 
 ** an attached table is modified and then later on the original values 
 ** are restored. However, if this function returns non-zero, then it is
 ** guaranteed that a call to sqlite3session_changeset() will return a 
 ** changeset containing zero changes.
 */
 SQLITE_API int sqlite3session_isempty(sqlite3_session *pSession);
 
 /*
 ** CAPI3REF: Create An Iterator To Traverse A Changeset 
 **
 ** Create an iterator used to iterate through the contents of a changeset.
 ** If successful, *pp is set to point to the iterator handle and SQLITE_OK
 ** is returned. Otherwise, if an error occurs, *pp is set to zero and an
 ** SQLite error code is returned.
 **
 ** The following functions can be used to advance and query a changeset 
 ** iterator created by this function:
 **
 ** <ul>
 **   <li> [sqlite3changeset_next()]
 **   <li> [sqlite3changeset_op()]
 **   <li> [sqlite3changeset_new()]
 **   <li> [sqlite3changeset_old()]
 ** </ul>
 **
 ** It is the responsibility of the caller to eventually destroy the iterator
 ** by passing it to [sqlite3changeset_finalize()]. The buffer containing the
 ** changeset (pChangeset) must remain valid until after the iterator is
 ** destroyed.
 **
 ** Assuming the changeset blob was created by one of the
 ** [sqlite3session_changeset()], [sqlite3changeset_concat()] or
 ** [sqlite3changeset_invert()] functions, all changes within the changeset 
 ** that apply to a single table are grouped together. This means that when 
 ** an application iterates through a changeset using an iterator created by 
 ** this function, all changes that relate to a single table are visited 
 ** consecutively. There is no chance that the iterator will visit a change 
 ** the applies to table X, then one for table Y, and then later on visit 
 ** another change for table X.
 */
 SQLITE_API int sqlite3changeset_start(
   sqlite3_changeset_iter **pp,    /* OUT: New changeset iterator handle */
   int nChangeset,                 /* Size of changeset blob in bytes */
   void *pChangeset                /* Pointer to blob containing changeset */
 );
 
 
 /*
 ** CAPI3REF: Advance A Changeset Iterator
 **
 ** This function may only be used with iterators created by function
 ** [sqlite3changeset_start()]. If it is called on an iterator passed to
 ** a conflict-handler callback by [sqlite3changeset_apply()], SQLITE_MISUSE
 ** is returned and the call has no effect.
 **
 ** Immediately after an iterator is created by sqlite3changeset_start(), it
 ** does not point to any change in the changeset. Assuming the changeset
 ** is not empty, the first call to this function advances the iterator to
 ** point to the first change in the changeset. Each subsequent call advances
 ** the iterator to point to the next change in the changeset (if any). If
 ** no error occurs and the iterator points to a valid change after a call
 ** to sqlite3changeset_next() has advanced it, SQLITE_ROW is returned. 
 ** Otherwise, if all changes in the changeset have already been visited,
 ** SQLITE_DONE is returned.
 **
 ** If an error occurs, an SQLite error code is returned. Possible error 
 ** codes include SQLITE_CORRUPT (if the changeset buffer is corrupt) or 
 ** SQLITE_NOMEM.
 */
 SQLITE_API int sqlite3changeset_next(sqlite3_changeset_iter *pIter);
 
 /*
 ** CAPI3REF: Obtain The Current Operation From A Changeset Iterator
 **
 ** The pIter argument passed to this function may either be an iterator
 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
 ** call to [sqlite3changeset_next()] must have returned [SQLITE_ROW]. If this
 ** is not the case, this function returns [SQLITE_MISUSE].
 **
 ** If argument pzTab is not NULL, then *pzTab is set to point to a
 ** nul-terminated utf-8 encoded string containing the name of the table
 ** affected by the current change. The buffer remains valid until either
 ** sqlite3changeset_next() is called on the iterator or until the 
 ** conflict-handler function returns. If pnCol is not NULL, then *pnCol is 
 ** set to the number of columns in the table affected by the change. If
 ** pbIncorrect is not NULL, then *pbIndirect is set to true (1) if the change
 ** is an indirect change, or false (0) otherwise. See the documentation for
 ** [sqlite3session_indirect()] for a description of direct and indirect
 ** changes. Finally, if pOp is not NULL, then *pOp is set to one of 
 ** [SQLITE_INSERT], [SQLITE_DELETE] or [SQLITE_UPDATE], depending on the 
 ** type of change that the iterator currently points to.
 **
 ** If no error occurs, SQLITE_OK is returned. If an error does occur, an
 ** SQLite error code is returned. The values of the output variables may not
 ** be trusted in this case.
 */
 SQLITE_API int sqlite3changeset_op(
   sqlite3_changeset_iter *pIter,  /* Iterator object */
   const char **pzTab,             /* OUT: Pointer to table name */
   int *pnCol,                     /* OUT: Number of columns in table */
   int *pOp,                       /* OUT: SQLITE_INSERT, DELETE or UPDATE */
   int *pbIndirect                 /* OUT: True for an 'indirect' change */
 );
 
 /*
 ** CAPI3REF: Obtain The Primary Key Definition Of A Table
 **
 ** For each modified table, a changeset includes the following:
 **
 ** <ul>
 **   <li> The number of columns in the table, and
 **   <li> Which of those columns make up the tables PRIMARY KEY.
 ** </ul>
 **
 ** This function is used to find which columns comprise the PRIMARY KEY of
 ** the table modified by the change that iterator pIter currently points to.
 ** If successful, *pabPK is set to point to an array of nCol entries, where
 ** nCol is the number of columns in the table. Elements of *pabPK are set to
 ** 0x01 if the corresponding column is part of the tables primary key, or
 ** 0x00 if it is not.
 **
 ** If argument pnCol is not NULL, then *pnCol is set to the number of columns
 ** in the table.
 **
 ** If this function is called when the iterator does not point to a valid
 ** entry, SQLITE_MISUSE is returned and the output variables zeroed. Otherwise,
 ** SQLITE_OK is returned and the output variables populated as described
 ** above.
 */
 SQLITE_API int sqlite3changeset_pk(
   sqlite3_changeset_iter *pIter,  /* Iterator object */
   unsigned char **pabPK,          /* OUT: Array of boolean - true for PK cols */
   int *pnCol                      /* OUT: Number of entries in output array */
 );
 
 /*
 ** CAPI3REF: Obtain old.* Values From A Changeset Iterator
 **
 ** The pIter argument passed to this function may either be an iterator
 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW. 
 ** Furthermore, it may only be called if the type of change that the iterator
 ** currently points to is either [SQLITE_DELETE] or [SQLITE_UPDATE]. Otherwise,
 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
 **
 ** Argument iVal must be greater than or equal to 0, and less than the number
 ** of columns in the table affected by the current change. Otherwise,
 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
 **
 ** If successful, this function sets *ppValue to point to a protected
 ** sqlite3_value object containing the iVal'th value from the vector of 
 ** original row values stored as part of the UPDATE or DELETE change and
 ** returns SQLITE_OK. The name of the function comes from the fact that this 
 ** is similar to the "old.*" columns available to update or delete triggers.
 **
 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
 ** is returned and *ppValue is set to NULL.
 */
 SQLITE_API int sqlite3changeset_old(
   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
   int iVal,                       /* Column number */
   sqlite3_value **ppValue         /* OUT: Old value (or NULL pointer) */
 );
 
 /*
 ** CAPI3REF: Obtain new.* Values From A Changeset Iterator
 **
 ** The pIter argument passed to this function may either be an iterator
 ** passed to a conflict-handler by [sqlite3changeset_apply()], or an iterator
 ** created by [sqlite3changeset_start()]. In the latter case, the most recent
 ** call to [sqlite3changeset_next()] must have returned SQLITE_ROW. 
 ** Furthermore, it may only be called if the type of change that the iterator
 ** currently points to is either [SQLITE_UPDATE] or [SQLITE_INSERT]. Otherwise,
 ** this function returns [SQLITE_MISUSE] and sets *ppValue to NULL.
 **
 ** Argument iVal must be greater than or equal to 0, and less than the number
 ** of columns in the table affected by the current change. Otherwise,
 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
 **
 ** If successful, this function sets *ppValue to point to a protected
 ** sqlite3_value object containing the iVal'th value from the vector of 
 ** new row values stored as part of the UPDATE or INSERT change and
 ** returns SQLITE_OK. If the change is an UPDATE and does not include
 ** a new value for the requested column, *ppValue is set to NULL and 
 ** SQLITE_OK returned. The name of the function comes from the fact that 
 ** this is similar to the "new.*" columns available to update or delete 
 ** triggers.
 **
 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
 ** is returned and *ppValue is set to NULL.
 */
 SQLITE_API int sqlite3changeset_new(
   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
   int iVal,                       /* Column number */
   sqlite3_value **ppValue         /* OUT: New value (or NULL pointer) */
 );
 
 /*
 ** CAPI3REF: Obtain Conflicting Row Values From A Changeset Iterator
 **
 ** This function should only be used with iterator objects passed to a
 ** conflict-handler callback by [sqlite3changeset_apply()] with either
 ** [SQLITE_CHANGESET_DATA] or [SQLITE_CHANGESET_CONFLICT]. If this function
 ** is called on any other iterator, [SQLITE_MISUSE] is returned and *ppValue
 ** is set to NULL.
 **
 ** Argument iVal must be greater than or equal to 0, and less than the number
 ** of columns in the table affected by the current change. Otherwise,
 ** [SQLITE_RANGE] is returned and *ppValue is set to NULL.
 **
 ** If successful, this function sets *ppValue to point to a protected
 ** sqlite3_value object containing the iVal'th value from the 
 ** "conflicting row" associated with the current conflict-handler callback
 ** and returns SQLITE_OK.
 **
 ** If some other error occurs (e.g. an OOM condition), an SQLite error code
 ** is returned and *ppValue is set to NULL.
 */
 SQLITE_API int sqlite3changeset_conflict(
   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
   int iVal,                       /* Column number */
   sqlite3_value **ppValue         /* OUT: Value from conflicting row */
 );
 
 /*
 ** CAPI3REF: Determine The Number Of Foreign Key Constraint Violations
 **
 ** This function may only be called with an iterator passed to an
 ** SQLITE_CHANGESET_FOREIGN_KEY conflict handler callback. In this case
 ** it sets the output variable to the total number of known foreign key
 ** violations in the destination database and returns SQLITE_OK.
 **
 ** In all other cases this function returns SQLITE_MISUSE.
 */
 SQLITE_API int sqlite3changeset_fk_conflicts(
   sqlite3_changeset_iter *pIter,  /* Changeset iterator */
   int *pnOut                      /* OUT: Number of FK violations */
 );
 
 
 /*
 ** CAPI3REF: Finalize A Changeset Iterator
 **
 ** This function is used to finalize an iterator allocated with
 ** [sqlite3changeset_start()].
 **
 ** This function should only be called on iterators created using the
 ** [sqlite3changeset_start()] function. If an application calls this
 ** function with an iterator passed to a conflict-handler by
 ** [sqlite3changeset_apply()], [SQLITE_MISUSE] is immediately returned and the
 ** call has no effect.
 **
 ** If an error was encountered within a call to an sqlite3changeset_xxx()
 ** function (for example an [SQLITE_CORRUPT] in [sqlite3changeset_next()] or an 
 ** [SQLITE_NOMEM] in [sqlite3changeset_new()]) then an error code corresponding
 ** to that error is returned by this function. Otherwise, SQLITE_OK is
 ** returned. This is to allow the following pattern (pseudo-code):
 **
 **   sqlite3changeset_start();
 **   while( SQLITE_ROW==sqlite3changeset_next() ){
 **     // Do something with change.
 **   }
 **   rc = sqlite3changeset_finalize();
 **   if( rc!=SQLITE_OK ){
 **     // An error has occurred 
 **   }
 */
 SQLITE_API int sqlite3changeset_finalize(sqlite3_changeset_iter *pIter);
 
 /*
 ** CAPI3REF: Invert A Changeset
 **
 ** This function is used to "invert" a changeset object. Applying an inverted
 ** changeset to a database reverses the effects of applying the uninverted
 ** changeset. Specifically:
 **
 ** <ul>
 **   <li> Each DELETE change is changed to an INSERT, and
 **   <li> Each INSERT change is changed to a DELETE, and
 **   <li> For each UPDATE change, the old.* and new.* values are exchanged.
 ** </ul>
 **
 ** This function does not change the order in which changes appear within
 ** the changeset. It merely reverses the sense of each individual change.
 **
 ** If successful, a pointer to a buffer containing the inverted changeset
 ** is stored in *ppOut, the size of the same buffer is stored in *pnOut, and
 ** SQLITE_OK is returned. If an error occurs, both *pnOut and *ppOut are
 ** zeroed and an SQLite error code returned.
 **
 ** It is the responsibility of the caller to eventually call sqlite3_free()
 ** on the *ppOut pointer to free the buffer allocation following a successful 
 ** call to this function.
 **
 ** WARNING/TODO: This function currently assumes that the input is a valid
 ** changeset. If it is not, the results are undefined.
 */
 SQLITE_API int sqlite3changeset_invert(
   int nIn, const void *pIn,       /* Input changeset */
   int *pnOut, void **ppOut        /* OUT: Inverse of input */
 );
 
 /*
 ** CAPI3REF: Concatenate Two Changeset Objects
 **
 ** This function is used to concatenate two changesets, A and B, into a 
 ** single changeset. The result is a changeset equivalent to applying
 ** changeset A followed by changeset B. 
 **
 ** This function combines the two input changesets using an 
 ** sqlite3_changegroup object. Calling it produces similar results as the
 ** following code fragment:
 **
 **   sqlite3_changegroup *pGrp;
 **   rc = sqlite3_changegroup_new(&pGrp);
 **   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nA, pA);
 **   if( rc==SQLITE_OK ) rc = sqlite3changegroup_add(pGrp, nB, pB);
 **   if( rc==SQLITE_OK ){
 **     rc = sqlite3changegroup_output(pGrp, pnOut, ppOut);
 **   }else{
 **     *ppOut = 0;
 **     *pnOut = 0;
 **   }
 **
 ** Refer to the sqlite3_changegroup documentation below for details.
 */
 SQLITE_API int sqlite3changeset_concat(
   int nA,                         /* Number of bytes in buffer pA */
   void *pA,                       /* Pointer to buffer containing changeset A */
   int nB,                         /* Number of bytes in buffer pB */
   void *pB,                       /* Pointer to buffer containing changeset B */
   int *pnOut,                     /* OUT: Number of bytes in output changeset */
   void **ppOut                    /* OUT: Buffer containing output changeset */
 );
 
 
 /*
 ** CAPI3REF: Changegroup Handle
 */
 typedef struct sqlite3_changegroup sqlite3_changegroup;
 
 /*
 ** CAPI3REF: Create A New Changegroup Object
 **
 ** An sqlite3_changegroup object is used to combine two or more changesets
 ** (or patchsets) into a single changeset (or patchset). A single changegroup
 ** object may combine changesets or patchsets, but not both. The output is
 ** always in the same format as the input.
 **
 ** If successful, this function returns SQLITE_OK and populates (*pp) with
 ** a pointer to a new sqlite3_changegroup object before returning. The caller
 ** should eventually free the returned object using a call to 
 ** sqlite3changegroup_delete(). If an error occurs, an SQLite error code
 ** (i.e. SQLITE_NOMEM) is returned and *pp is set to NULL.
 **
 ** The usual usage pattern for an sqlite3_changegroup object is as follows:
 **
 ** <ul>
 **   <li> It is created using a call to sqlite3changegroup_new().
 **
 **   <li> Zero or more changesets (or patchsets) are added to the object
 **        by calling sqlite3changegroup_add().
 **
 **   <li> The result of combining all input changesets together is obtained 
 **        by the application via a call to sqlite3changegroup_output().
 **
 **   <li> The object is deleted using a call to sqlite3changegroup_delete().
 ** </ul>
 **
 ** Any number of calls to add() and output() may be made between the calls to
 ** new() and delete(), and in any order.
 **
 ** As well as the regular sqlite3changegroup_add() and 
 ** sqlite3changegroup_output() functions, also available are the streaming
 ** versions sqlite3changegroup_add_strm() and sqlite3changegroup_output_strm().
 */
 SQLITE_API int sqlite3changegroup_new(sqlite3_changegroup **pp);
 
 /*
 ** CAPI3REF: Add A Changeset To A Changegroup
 **
 ** Add all changes within the changeset (or patchset) in buffer pData (size
 ** nData bytes) to the changegroup. 
 **
 ** If the buffer contains a patchset, then all prior calls to this function
 ** on the same changegroup object must also have specified patchsets. Or, if
 ** the buffer contains a changeset, so must have the earlier calls to this
 ** function. Otherwise, SQLITE_ERROR is returned and no changes are added
 ** to the changegroup.
 **
 ** Rows within the changeset and changegroup are identified by the values in
 ** their PRIMARY KEY columns. A change in the changeset is considered to
 ** apply to the same row as a change already present in the changegroup if
 ** the two rows have the same primary key.
 **
 ** Changes to rows that do not already appear in the changegroup are
 ** simply copied into it. Or, if both the new changeset and the changegroup
 ** contain changes that apply to a single row, the final contents of the
 ** changegroup depends on the type of each change, as follows:
 **
 ** <table border=1 style="margin-left:8ex;margin-right:8ex">
 **   <tr><th style="white-space:pre">Existing Change  </th>
 **       <th style="white-space:pre">New Change       </th>
 **       <th>Output Change
 **   <tr><td>INSERT <td>INSERT <td>
 **       The new change is ignored. This case does not occur if the new
 **       changeset was recorded immediately after the changesets already
 **       added to the changegroup.
 **   <tr><td>INSERT <td>UPDATE <td>
 **       The INSERT change remains in the changegroup. The values in the 
 **       INSERT change are modified as if the row was inserted by the
 **       existing change and then updated according to the new change.
 **   <tr><td>INSERT <td>DELETE <td>
 **       The existing INSERT is removed from the changegroup. The DELETE is
 **       not added.
 **   <tr><td>UPDATE <td>INSERT <td>
 **       The new change is ignored. This case does not occur if the new
 **       changeset was recorded immediately after the changesets already
 **       added to the changegroup.
 **   <tr><td>UPDATE <td>UPDATE <td>
 **       The existing UPDATE remains within the changegroup. It is amended 
 **       so that the accompanying values are as if the row was updated once 
 **       by the existing change and then again by the new change.
 **   <tr><td>UPDATE <td>DELETE <td>
 **       The existing UPDATE is replaced by the new DELETE within the
 **       changegroup.
 **   <tr><td>DELETE <td>INSERT <td>
 **       If one or more of the column values in the row inserted by the
 **       new change differ from those in the row deleted by the existing 
 **       change, the existing DELETE is replaced by an UPDATE within the
 **       changegroup. Otherwise, if the inserted row is exactly the same 
 **       as the deleted row, the existing DELETE is simply discarded.
 **   <tr><td>DELETE <td>UPDATE <td>
 **       The new change is ignored. This case does not occur if the new
 **       changeset was recorded immediately after the changesets already
 **       added to the changegroup.
 **   <tr><td>DELETE <td>DELETE <td>
 **       The new change is ignored. This case does not occur if the new
 **       changeset was recorded immediately after the changesets already
 **       added to the changegroup.
 ** </table>
 **
 ** If the new changeset contains changes to a table that is already present
 ** in the changegroup, then the number of columns and the position of the
 ** primary key columns for the table must be consistent. If this is not the
 ** case, this function fails with SQLITE_SCHEMA. If the input changeset
 ** appears to be corrupt and the corruption is detected, SQLITE_CORRUPT is
 ** returned. Or, if an out-of-memory condition occurs during processing, this
 ** function returns SQLITE_NOMEM. In all cases, if an error occurs the
 ** final contents of the changegroup is undefined.
 **
 ** If no error occurs, SQLITE_OK is returned.
 */
 SQLITE_API int sqlite3changegroup_add(sqlite3_changegroup*, int nData, void *pData);
 
 /*
 ** CAPI3REF: Obtain A Composite Changeset From A Changegroup
 **
 ** Obtain a buffer containing a changeset (or patchset) representing the
 ** current contents of the changegroup. If the inputs to the changegroup
 ** were themselves changesets, the output is a changeset. Or, if the
 ** inputs were patchsets, the output is also a patchset.
 **
 ** As with the output of the sqlite3session_changeset() and
 ** sqlite3session_patchset() functions, all changes related to a single
 ** table are grouped together in the output of this function. Tables appear
 ** in the same order as for the very first changeset added to the changegroup.
 ** If the second or subsequent changesets added to the changegroup contain
 ** changes for tables that do not appear in the first changeset, they are
 ** appended onto the end of the output changeset, again in the order in
 ** which they are first encountered.
 **
 ** If an error occurs, an SQLite error code is returned and the output
 ** variables (*pnData) and (*ppData) are set to 0. Otherwise, SQLITE_OK
 ** is returned and the output variables are set to the size of and a 
 ** pointer to the output buffer, respectively. In this case it is the
 ** responsibility of the caller to eventually free the buffer using a
 ** call to sqlite3_free().
 */
 SQLITE_API int sqlite3changegroup_output(
   sqlite3_changegroup*,
   int *pnData,                    /* OUT: Size of output buffer in bytes */
   void **ppData                   /* OUT: Pointer to output buffer */
 );
 
 /*
 ** CAPI3REF: Delete A Changegroup Object
 */
 SQLITE_API void sqlite3changegroup_delete(sqlite3_changegroup*);
 
 /*
 ** CAPI3REF: Apply A Changeset To A Database
 **
 ** Apply a changeset to a database. This function attempts to update the
 ** "main" database attached to handle db with the changes found in the
 ** changeset passed via the second and third arguments.
 **
 ** The fourth argument (xFilter) passed to this function is the "filter
 ** callback". If it is not NULL, then for each table affected by at least one
 ** change in the changeset, the filter callback is invoked with
 ** the table name as the second argument, and a copy of the context pointer
 ** passed as the sixth argument to this function as the first. If the "filter
 ** callback" returns zero, then no attempt is made to apply any changes to 
 ** the table. Otherwise, if the return value is non-zero or the xFilter
 ** argument to this function is NULL, all changes related to the table are
 ** attempted.
 **
 ** For each table that is not excluded by the filter callback, this function 
 ** tests that the target database contains a compatible table. A table is 
 ** considered compatible if all of the following are true:
 **
 ** <ul>
 **   <li> The table has the same name as the name recorded in the 
 **        changeset, and
 **   <li> The table has at least as many columns as recorded in the 
 **        changeset, and
 **   <li> The table has primary key columns in the same position as 
 **        recorded in the changeset.
 ** </ul>
 **
 ** If there is no compatible table, it is not an error, but none of the
 ** changes associated with the table are applied. A warning message is issued
 ** via the sqlite3_log() mechanism with the error code SQLITE_SCHEMA. At most
 ** one such warning is issued for each table in the changeset.
 **
 ** For each change for which there is a compatible table, an attempt is made 
 ** to modify the table contents according to the UPDATE, INSERT or DELETE 
 ** change. If a change cannot be applied cleanly, the conflict handler 
 ** function passed as the fifth argument to sqlite3changeset_apply() may be 
 ** invoked. A description of exactly when the conflict handler is invoked for 
 ** each type of change is below.
 **
 ** Unlike the xFilter argument, xConflict may not be passed NULL. The results
 ** of passing anything other than a valid function pointer as the xConflict
 ** argument are undefined.
 **
 ** Each time the conflict handler function is invoked, it must return one
 ** of [SQLITE_CHANGESET_OMIT], [SQLITE_CHANGESET_ABORT] or 
 ** [SQLITE_CHANGESET_REPLACE]. SQLITE_CHANGESET_REPLACE may only be returned
 ** if the second argument passed to the conflict handler is either
 ** SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If the conflict-handler
 ** returns an illegal value, any changes already made are rolled back and
 ** the call to sqlite3changeset_apply() returns SQLITE_MISUSE. Different 
 ** actions are taken by sqlite3changeset_apply() depending on the value
 ** returned by each invocation of the conflict-handler function. Refer to
 ** the documentation for the three 
 ** [SQLITE_CHANGESET_OMIT|available return values] for details.
 **
 ** <dl>
 ** <dt>DELETE Changes<dd>
 **   For each DELETE change, this function checks if the target database 
 **   contains a row with the same primary key value (or values) as the 
 **   original row values stored in the changeset. If it does, and the values 
 **   stored in all non-primary key columns also match the values stored in 
 **   the changeset the row is deleted from the target database.
 **
 **   If a row with matching primary key values is found, but one or more of
 **   the non-primary key fields contains a value different from the original
 **   row value stored in the changeset, the conflict-handler function is
 **   invoked with [SQLITE_CHANGESET_DATA] as the second argument. If the
 **   database table has more columns than are recorded in the changeset,
 **   only the values of those non-primary key fields are compared against
 **   the current database contents - any trailing database table columns
 **   are ignored.
 **
 **   If no row with matching primary key values is found in the database,
 **   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
 **   passed as the second argument.
 **
 **   If the DELETE operation is attempted, but SQLite returns SQLITE_CONSTRAINT
 **   (which can only happen if a foreign key constraint is violated), the
 **   conflict-handler function is invoked with [SQLITE_CHANGESET_CONSTRAINT]
 **   passed as the second argument. This includes the case where the DELETE
 **   operation is attempted because an earlier call to the conflict handler
 **   function returned [SQLITE_CHANGESET_REPLACE].
 **
 ** <dt>INSERT Changes<dd>
 **   For each INSERT change, an attempt is made to insert the new row into
 **   the database. If the changeset row contains fewer fields than the
 **   database table, the trailing fields are populated with their default
 **   values.
 **
 **   If the attempt to insert the row fails because the database already 
 **   contains a row with the same primary key values, the conflict handler
 **   function is invoked with the second argument set to 
 **   [SQLITE_CHANGESET_CONFLICT].
 **
 **   If the attempt to insert the row fails because of some other constraint
 **   violation (e.g. NOT NULL or UNIQUE), the conflict handler function is 
 **   invoked with the second argument set to [SQLITE_CHANGESET_CONSTRAINT].
 **   This includes the case where the INSERT operation is re-attempted because 
 **   an earlier call to the conflict handler function returned 
 **   [SQLITE_CHANGESET_REPLACE].
 **
 ** <dt>UPDATE Changes<dd>
 **   For each UPDATE change, this function checks if the target database 
 **   contains a row with the same primary key value (or values) as the 
 **   original row values stored in the changeset. If it does, and the values 
 **   stored in all modified non-primary key columns also match the values
 **   stored in the changeset the row is updated within the target database.
 **
 **   If a row with matching primary key values is found, but one or more of
 **   the modified non-primary key fields contains a value different from an
 **   original row value stored in the changeset, the conflict-handler function
 **   is invoked with [SQLITE_CHANGESET_DATA] as the second argument. Since
 **   UPDATE changes only contain values for non-primary key fields that are
 **   to be modified, only those fields need to match the original values to
 **   avoid the SQLITE_CHANGESET_DATA conflict-handler callback.
 **
 **   If no row with matching primary key values is found in the database,
 **   the conflict-handler function is invoked with [SQLITE_CHANGESET_NOTFOUND]
 **   passed as the second argument.
 **
 **   If the UPDATE operation is attempted, but SQLite returns 
 **   SQLITE_CONSTRAINT, the conflict-handler function is invoked with 
 **   [SQLITE_CHANGESET_CONSTRAINT] passed as the second argument.
 **   This includes the case where the UPDATE operation is attempted after 
 **   an earlier call to the conflict handler function returned
 **   [SQLITE_CHANGESET_REPLACE].  
 ** </dl>
 **
 ** It is safe to execute SQL statements, including those that write to the
 ** table that the callback related to, from within the xConflict callback.
 ** This can be used to further customize the applications conflict
 ** resolution strategy.
 **
 ** All changes made by this function are enclosed in a savepoint transaction.
 ** If any other error (aside from a constraint failure when attempting to
 ** write to the target database) occurs, then the savepoint transaction is
 ** rolled back, restoring the target database to its original state, and an 
 ** SQLite error code returned.
 */
 SQLITE_API int sqlite3changeset_apply(
   sqlite3 *db,                    /* Apply change to "main" db of this handle */
   int nChangeset,                 /* Size of changeset in bytes */
   void *pChangeset,               /* Changeset blob */
   int(*xFilter)(
     void *pCtx,                   /* Copy of sixth arg to _apply() */
     const char *zTab              /* Table name */
   ),
   int(*xConflict)(
     void *pCtx,                   /* Copy of sixth arg to _apply() */
     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
   ),
   void *pCtx                      /* First argument passed to xConflict */
 );
 
 /* 
 ** CAPI3REF: Constants Passed To The Conflict Handler
 **
 ** Values that may be passed as the second argument to a conflict-handler.
 **
 ** <dl>
 ** <dt>SQLITE_CHANGESET_DATA<dd>
 **   The conflict handler is invoked with CHANGESET_DATA as the second argument
 **   when processing a DELETE or UPDATE change if a row with the required
 **   PRIMARY KEY fields is present in the database, but one or more other 
 **   (non primary-key) fields modified by the update do not contain the 
 **   expected "before" values.
 ** 
 **   The conflicting row, in this case, is the database row with the matching
 **   primary key.
 ** 
 ** <dt>SQLITE_CHANGESET_NOTFOUND<dd>
 **   The conflict handler is invoked with CHANGESET_NOTFOUND as the second
 **   argument when processing a DELETE or UPDATE change if a row with the
 **   required PRIMARY KEY fields is not present in the database.
 ** 
 **   There is no conflicting row in this case. The results of invoking the
 **   sqlite3changeset_conflict() API are undefined.
 ** 
 ** <dt>SQLITE_CHANGESET_CONFLICT<dd>
 **   CHANGESET_CONFLICT is passed as the second argument to the conflict
 **   handler while processing an INSERT change if the operation would result 
 **   in duplicate primary key values.
 ** 
 **   The conflicting row in this case is the database row with the matching
 **   primary key.
 **
 ** <dt>SQLITE_CHANGESET_FOREIGN_KEY<dd>
 **   If foreign key handling is enabled, and applying a changeset leaves the
 **   database in a state containing foreign key violations, the conflict 
 **   handler is invoked with CHANGESET_FOREIGN_KEY as the second argument
 **   exactly once before the changeset is committed. If the conflict handler
 **   returns CHANGESET_OMIT, the changes, including those that caused the
 **   foreign key constraint violation, are committed. Or, if it returns
 **   CHANGESET_ABORT, the changeset is rolled back.
 **
 **   No current or conflicting row information is provided. The only function
 **   it is possible to call on the supplied sqlite3_changeset_iter handle
 **   is sqlite3changeset_fk_conflicts().
 ** 
 ** <dt>SQLITE_CHANGESET_CONSTRAINT<dd>
 **   If any other constraint violation occurs while applying a change (i.e. 
 **   a UNIQUE, CHECK or NOT NULL constraint), the conflict handler is 
 **   invoked with CHANGESET_CONSTRAINT as the second argument.
 ** 
 **   There is no conflicting row in this case. The results of invoking the
 **   sqlite3changeset_conflict() API are undefined.
 **
 ** </dl>
 */
 #define SQLITE_CHANGESET_DATA        1
 #define SQLITE_CHANGESET_NOTFOUND    2
 #define SQLITE_CHANGESET_CONFLICT    3
 #define SQLITE_CHANGESET_CONSTRAINT  4
 #define SQLITE_CHANGESET_FOREIGN_KEY 5
 
 /* 
 ** CAPI3REF: Constants Returned By The Conflict Handler
 **
 ** A conflict handler callback must return one of the following three values.
 **
 ** <dl>
 ** <dt>SQLITE_CHANGESET_OMIT<dd>
 **   If a conflict handler returns this value no special action is taken. The
 **   change that caused the conflict is not applied. The session module 
 **   continues to the next change in the changeset.
 **
 ** <dt>SQLITE_CHANGESET_REPLACE<dd>
 **   This value may only be returned if the second argument to the conflict
 **   handler was SQLITE_CHANGESET_DATA or SQLITE_CHANGESET_CONFLICT. If this
 **   is not the case, any changes applied so far are rolled back and the 
 **   call to sqlite3changeset_apply() returns SQLITE_MISUSE.
 **
 **   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_DATA conflict
 **   handler, then the conflicting row is either updated or deleted, depending
 **   on the type of change.
 **
 **   If CHANGESET_REPLACE is returned by an SQLITE_CHANGESET_CONFLICT conflict
 **   handler, then the conflicting row is removed from the database and a
 **   second attempt to apply the change is made. If this second attempt fails,
 **   the original row is restored to the database before continuing.
 **
 ** <dt>SQLITE_CHANGESET_ABORT<dd>
 **   If this value is returned, any changes applied so far are rolled back 
 **   and the call to sqlite3changeset_apply() returns SQLITE_ABORT.
 ** </dl>
 */
 #define SQLITE_CHANGESET_OMIT       0
 #define SQLITE_CHANGESET_REPLACE    1
 #define SQLITE_CHANGESET_ABORT      2
 
 /*
 ** CAPI3REF: Streaming Versions of API functions.
 **
 ** The six streaming API xxx_strm() functions serve similar purposes to the 
 ** corresponding non-streaming API functions:
 **
 ** <table border=1 style="margin-left:8ex;margin-right:8ex">
 **   <tr><th>Streaming function<th>Non-streaming equivalent</th>
 **   <tr><td>sqlite3changeset_apply_strm<td>[sqlite3changeset_apply] 
 **   <tr><td>sqlite3changeset_concat_strm<td>[sqlite3changeset_concat] 
 **   <tr><td>sqlite3changeset_invert_strm<td>[sqlite3changeset_invert] 
 **   <tr><td>sqlite3changeset_start_strm<td>[sqlite3changeset_start] 
 **   <tr><td>sqlite3session_changeset_strm<td>[sqlite3session_changeset] 
 **   <tr><td>sqlite3session_patchset_strm<td>[sqlite3session_patchset] 
 ** </table>
 **
 ** Non-streaming functions that accept changesets (or patchsets) as input
 ** require that the entire changeset be stored in a single buffer in memory. 
 ** Similarly, those that return a changeset or patchset do so by returning 
 ** a pointer to a single large buffer allocated using sqlite3_malloc(). 
 ** Normally this is convenient. However, if an application running in a 
 ** low-memory environment is required to handle very large changesets, the
 ** large contiguous memory allocations required can become onerous.
 **
 ** In order to avoid this problem, instead of a single large buffer, input
 ** is passed to a streaming API functions by way of a callback function that
 ** the sessions module invokes to incrementally request input data as it is
 ** required. In all cases, a pair of API function parameters such as
 **
 **  <pre>
 **  &nbsp;     int nChangeset,
 **  &nbsp;     void *pChangeset,
 **  </pre>
 **
 ** Is replaced by:
 **
 **  <pre>
 **  &nbsp;     int (*xInput)(void *pIn, void *pData, int *pnData),
 **  &nbsp;     void *pIn,
 **  </pre>
 **
 ** Each time the xInput callback is invoked by the sessions module, the first
 ** argument passed is a copy of the supplied pIn context pointer. The second 
 ** argument, pData, points to a buffer (*pnData) bytes in size. Assuming no 
 ** error occurs the xInput method should copy up to (*pnData) bytes of data 
 ** into the buffer and set (*pnData) to the actual number of bytes copied 
 ** before returning SQLITE_OK. If the input is completely exhausted, (*pnData) 
 ** should be set to zero to indicate this. Or, if an error occurs, an SQLite 
 ** error code should be returned. In all cases, if an xInput callback returns
 ** an error, all processing is abandoned and the streaming API function
 ** returns a copy of the error code to the caller.
 **
 ** In the case of sqlite3changeset_start_strm(), the xInput callback may be
 ** invoked by the sessions module at any point during the lifetime of the
 ** iterator. If such an xInput callback returns an error, the iterator enters
 ** an error state, whereby all subsequent calls to iterator functions 
 ** immediately fail with the same error code as returned by xInput.
 **
 ** Similarly, streaming API functions that return changesets (or patchsets)
 ** return them in chunks by way of a callback function instead of via a
 ** pointer to a single large buffer. In this case, a pair of parameters such
 ** as:
 **
 **  <pre>
 **  &nbsp;     int *pnChangeset,
 **  &nbsp;     void **ppChangeset,
 **  </pre>
 **
 ** Is replaced by:
 **
 **  <pre>
 **  &nbsp;     int (*xOutput)(void *pOut, const void *pData, int nData),
 **  &nbsp;     void *pOut
 **  </pre>
 **
 ** The xOutput callback is invoked zero or more times to return data to
 ** the application. The first parameter passed to each call is a copy of the
 ** pOut pointer supplied by the application. The second parameter, pData,
 ** points to a buffer nData bytes in size containing the chunk of output
 ** data being returned. If the xOutput callback successfully processes the
 ** supplied data, it should return SQLITE_OK to indicate success. Otherwise,
 ** it should return some other SQLite error code. In this case processing
 ** is immediately abandoned and the streaming API function returns a copy
 ** of the xOutput error code to the application.
 **
 ** The sessions module never invokes an xOutput callback with the third 
 ** parameter set to a value less than or equal to zero. Other than this,
 ** no guarantees are made as to the size of the chunks of data returned.
 */
 SQLITE_API int sqlite3changeset_apply_strm(
   sqlite3 *db,                    /* Apply change to "main" db of this handle */
   int (*xInput)(void *pIn, void *pData, int *pnData), /* Input function */
   void *pIn,                                          /* First arg for xInput */
   int(*xFilter)(
     void *pCtx,                   /* Copy of sixth arg to _apply() */
     const char *zTab              /* Table name */
   ),
   int(*xConflict)(
     void *pCtx,                   /* Copy of sixth arg to _apply() */
     int eConflict,                /* DATA, MISSING, CONFLICT, CONSTRAINT */
     sqlite3_changeset_iter *p     /* Handle describing change and conflict */
   ),
   void *pCtx                      /* First argument passed to xConflict */
 );
 SQLITE_API int sqlite3changeset_concat_strm(
   int (*xInputA)(void *pIn, void *pData, int *pnData),
   void *pInA,
   int (*xInputB)(void *pIn, void *pData, int *pnData),
   void *pInB,
   int (*xOutput)(void *pOut, const void *pData, int nData),
   void *pOut
 );
 SQLITE_API int sqlite3changeset_invert_strm(
   int (*xInput)(void *pIn, void *pData, int *pnData),
   void *pIn,
   int (*xOutput)(void *pOut, const void *pData, int nData),
   void *pOut
 );
 SQLITE_API int sqlite3changeset_start_strm(
   sqlite3_changeset_iter **pp,
   int (*xInput)(void *pIn, void *pData, int *pnData),
   void *pIn
 );
 SQLITE_API int sqlite3session_changeset_strm(
   sqlite3_session *pSession,
   int (*xOutput)(void *pOut, const void *pData, int nData),
   void *pOut
 );
 SQLITE_API int sqlite3session_patchset_strm(
   sqlite3_session *pSession,
   int (*xOutput)(void *pOut, const void *pData, int nData),
   void *pOut
 );
 SQLITE_API int sqlite3changegroup_add_strm(sqlite3_changegroup*, 
     int (*xInput)(void *pIn, void *pData, int *pnData),
     void *pIn
 );
 SQLITE_API int sqlite3changegroup_output_strm(sqlite3_changegroup*,
     int (*xOutput)(void *pOut, const void *pData, int nData), 
     void *pOut
 );
 
 
 /*
 ** Make sure we can call this stuff from C++.
 */
 #ifdef __cplusplus
 }
 #endif
 
 #endif  /* !defined(__SQLITESESSION_H_) && defined(SQLITE_ENABLE_SESSION) */
 
 /******** End of sqlite3session.h *********/
 /******** Begin file fts5.h *********/
 /*
 ** 2014 May 31
 **
 ** The author disclaims copyright to this source code.  In place of
 ** a legal notice, here is a blessing:
 **
 **    May you do good and not evil.
 **    May you find forgiveness for yourself and forgive others.
 **    May you share freely, never taking more than you give.
 **
 ******************************************************************************
 **
 ** Interfaces to extend FTS5. Using the interfaces defined in this file, 
 ** FTS5 may be extended with:
 **
 **     * custom tokenizers, and
 **     * custom auxiliary functions.
 */
 
 
 #ifndef _FTS5_H
 #define _FTS5_H
 
 
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /*************************************************************************
 ** CUSTOM AUXILIARY FUNCTIONS
 **
 ** Virtual table implementations may overload SQL functions by implementing
 ** the sqlite3_module.xFindFunction() method.
 */
 
 typedef struct Fts5ExtensionApi Fts5ExtensionApi;
 typedef struct Fts5Context Fts5Context;
 typedef struct Fts5PhraseIter Fts5PhraseIter;
 
 typedef void (*fts5_extension_function)(
   const Fts5ExtensionApi *pApi,   /* API offered by current FTS version */
   Fts5Context *pFts,              /* First arg to pass to pApi functions */
   sqlite3_context *pCtx,          /* Context for returning result/error */
   int nVal,                       /* Number of values in apVal[] array */
   sqlite3_value **apVal           /* Array of trailing arguments */
 );
 
 struct Fts5PhraseIter {
   const unsigned char *a;
   const unsigned char *b;
 };
 
 /*
 ** EXTENSION API FUNCTIONS
 **
 ** xUserData(pFts):
 **   Return a copy of the context pointer the extension function was 
 **   registered with.
 **
 ** xColumnTotalSize(pFts, iCol, pnToken):
 **   If parameter iCol is less than zero, set output variable *pnToken
 **   to the total number of tokens in the FTS5 table. Or, if iCol is
 **   non-negative but less than the number of columns in the table, return
 **   the total number of tokens in column iCol, considering all rows in 
 **   the FTS5 table.
 **
 **   If parameter iCol is greater than or equal to the number of columns
 **   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
 **   an OOM condition or IO error), an appropriate SQLite error code is 
 **   returned.
 **
 ** xColumnCount(pFts):
 **   Return the number of columns in the table.
 **
 ** xColumnSize(pFts, iCol, pnToken):
 **   If parameter iCol is less than zero, set output variable *pnToken
 **   to the total number of tokens in the current row. Or, if iCol is
 **   non-negative but less than the number of columns in the table, set
 **   *pnToken to the number of tokens in column iCol of the current row.
 **
 **   If parameter iCol is greater than or equal to the number of columns
 **   in the table, SQLITE_RANGE is returned. Or, if an error occurs (e.g.
 **   an OOM condition or IO error), an appropriate SQLite error code is 
 **   returned.
 **
 **   This function may be quite inefficient if used with an FTS5 table
 **   created with the "columnsize=0" option.
 **
 ** xColumnText:
 **   This function attempts to retrieve the text of column iCol of the
 **   current document. If successful, (*pz) is set to point to a buffer
 **   containing the text in utf-8 encoding, (*pn) is set to the size in bytes
 **   (not characters) of the buffer and SQLITE_OK is returned. Otherwise,
 **   if an error occurs, an SQLite error code is returned and the final values
 **   of (*pz) and (*pn) are undefined.
 **
 ** xPhraseCount:
 **   Returns the number of phrases in the current query expression.
 **
 ** xPhraseSize:
 **   Returns the number of tokens in phrase iPhrase of the query. Phrases
 **   are numbered starting from zero.
 **
 ** xInstCount:
 **   Set *pnInst to the total number of occurrences of all phrases within
 **   the query within the current row. Return SQLITE_OK if successful, or
 **   an error code (i.e. SQLITE_NOMEM) if an error occurs.
 **
 **   This API can be quite slow if used with an FTS5 table created with the
 **   "detail=none" or "detail=column" option. If the FTS5 table is created 
 **   with either "detail=none" or "detail=column" and "content=" option 
 **   (i.e. if it is a contentless table), then this API always returns 0.
 **
 ** xInst:
 **   Query for the details of phrase match iIdx within the current row.
 **   Phrase matches are numbered starting from zero, so the iIdx argument
 **   should be greater than or equal to zero and smaller than the value
 **   output by xInstCount().
 **
 **   Usually, output parameter *piPhrase is set to the phrase number, *piCol
 **   to the column in which it occurs and *piOff the token offset of the
 **   first token of the phrase. The exception is if the table was created
 **   with the offsets=0 option specified. In this case *piOff is always
 **   set to -1.
 **
 **   Returns SQLITE_OK if successful, or an error code (i.e. SQLITE_NOMEM) 
 **   if an error occurs.
 **
 **   This API can be quite slow if used with an FTS5 table created with the
 **   "detail=none" or "detail=column" option. 
 **
 ** xRowid:
 **   Returns the rowid of the current row.
 **
 ** xTokenize:
 **   Tokenize text using the tokenizer belonging to the FTS5 table.
 **
 ** xQueryPhrase(pFts5, iPhrase, pUserData, xCallback):
 **   This API function is used to query the FTS table for phrase iPhrase
 **   of the current query. Specifically, a query equivalent to:
 **
 **       ... FROM ftstable WHERE ftstable MATCH $p ORDER BY rowid
 **
 **   with $p set to a phrase equivalent to the phrase iPhrase of the
 **   current query is executed. Any column filter that applies to
 **   phrase iPhrase of the current query is included in $p. For each 
 **   row visited, the callback function passed as the fourth argument 
 **   is invoked. The context and API objects passed to the callback 
 **   function may be used to access the properties of each matched row.
 **   Invoking Api.xUserData() returns a copy of the pointer passed as 
 **   the third argument to pUserData.
 **
 **   If the callback function returns any value other than SQLITE_OK, the
 **   query is abandoned and the xQueryPhrase function returns immediately.
 **   If the returned value is SQLITE_DONE, xQueryPhrase returns SQLITE_OK.
 **   Otherwise, the error code is propagated upwards.
 **
 **   If the query runs to completion without incident, SQLITE_OK is returned.
 **   Or, if some error occurs before the query completes or is aborted by
 **   the callback, an SQLite error code is returned.
 **
 **
 ** xSetAuxdata(pFts5, pAux, xDelete)
 **
 **   Save the pointer passed as the second argument as the extension functions 
 **   "auxiliary data". The pointer may then be retrieved by the current or any
 **   future invocation of the same fts5 extension function made as part of
 **   of the same MATCH query using the xGetAuxdata() API.
 **
 **   Each extension function is allocated a single auxiliary data slot for
 **   each FTS query (MATCH expression). If the extension function is invoked 
 **   more than once for a single FTS query, then all invocations share a 
 **   single auxiliary data context.
 **
 **   If there is already an auxiliary data pointer when this function is
 **   invoked, then it is replaced by the new pointer. If an xDelete callback
 **   was specified along with the original pointer, it is invoked at this
 **   point.
 **
 **   The xDelete callback, if one is specified, is also invoked on the
 **   auxiliary data pointer after the FTS5 query has finished.
 **
 **   If an error (e.g. an OOM condition) occurs within this function, an
 **   the auxiliary data is set to NULL and an error code returned. If the
 **   xDelete parameter was not NULL, it is invoked on the auxiliary data
 **   pointer before returning.
 **
 **
 ** xGetAuxdata(pFts5, bClear)
 **
 **   Returns the current auxiliary data pointer for the fts5 extension 
 **   function. See the xSetAuxdata() method for details.
 **
 **   If the bClear argument is non-zero, then the auxiliary data is cleared
 **   (set to NULL) before this function returns. In this case the xDelete,
 **   if any, is not invoked.
 **
 **
 ** xRowCount(pFts5, pnRow)
 **
 **   This function is used to retrieve the total number of rows in the table.
 **   In other words, the same value that would be returned by:
 **
 **        SELECT count(*) FROM ftstable;
 **
 ** xPhraseFirst()
 **   This function is used, along with type Fts5PhraseIter and the xPhraseNext
 **   method, to iterate through all instances of a single query phrase within
 **   the current row. This is the same information as is accessible via the
 **   xInstCount/xInst APIs. While the xInstCount/xInst APIs are more convenient
 **   to use, this API may be faster under some circumstances. To iterate 
 **   through instances of phrase iPhrase, use the following code:
 **
 **       Fts5PhraseIter iter;
 **       int iCol, iOff;
 **       for(pApi->xPhraseFirst(pFts, iPhrase, &iter, &iCol, &iOff);
 **           iCol>=0;
 **           pApi->xPhraseNext(pFts, &iter, &iCol, &iOff)
 **       ){
 **         // An instance of phrase iPhrase at offset iOff of column iCol
 **       }
 **
 **   The Fts5PhraseIter structure is defined above. Applications should not
 **   modify this structure directly - it should only be used as shown above
 **   with the xPhraseFirst() and xPhraseNext() API methods (and by
 **   xPhraseFirstColumn() and xPhraseNextColumn() as illustrated below).
 **
 **   This API can be quite slow if used with an FTS5 table created with the
 **   "detail=none" or "detail=column" option. If the FTS5 table is created 
 **   with either "detail=none" or "detail=column" and "content=" option 
 **   (i.e. if it is a contentless table), then this API always iterates
 **   through an empty set (all calls to xPhraseFirst() set iCol to -1).
 **
 ** xPhraseNext()
 **   See xPhraseFirst above.
 **
 ** xPhraseFirstColumn()
 **   This function and xPhraseNextColumn() are similar to the xPhraseFirst()
 **   and xPhraseNext() APIs described above. The difference is that instead
 **   of iterating through all instances of a phrase in the current row, these
 **   APIs are used to iterate through the set of columns in the current row
 **   that contain one or more instances of a specified phrase. For example:
 **
 **       Fts5PhraseIter iter;
 **       int iCol;
 **       for(pApi->xPhraseFirstColumn(pFts, iPhrase, &iter, &iCol);
 **           iCol>=0;
 **           pApi->xPhraseNextColumn(pFts, &iter, &iCol)
 **       ){
 **         // Column iCol contains at least one instance of phrase iPhrase
 **       }
 **
 **   This API can be quite slow if used with an FTS5 table created with the
 **   "detail=none" option. If the FTS5 table is created with either 
 **   "detail=none" "content=" option (i.e. if it is a contentless table), 
 **   then this API always iterates through an empty set (all calls to 
 **   xPhraseFirstColumn() set iCol to -1).
 **
 **   The information accessed using this API and its companion
 **   xPhraseFirstColumn() may also be obtained using xPhraseFirst/xPhraseNext
 **   (or xInst/xInstCount). The chief advantage of this API is that it is
 **   significantly more efficient than those alternatives when used with
 **   "detail=column" tables.  
 **
 ** xPhraseNextColumn()
 **   See xPhraseFirstColumn above.
 */
 struct Fts5ExtensionApi {
   int iVersion;                   /* Currently always set to 3 */
 
   void *(*xUserData)(Fts5Context*);
 
   int (*xColumnCount)(Fts5Context*);
   int (*xRowCount)(Fts5Context*, sqlite3_int64 *pnRow);
   int (*xColumnTotalSize)(Fts5Context*, int iCol, sqlite3_int64 *pnToken);
 
   int (*xTokenize)(Fts5Context*, 
     const char *pText, int nText, /* Text to tokenize */
     void *pCtx,                   /* Context passed to xToken() */
     int (*xToken)(void*, int, const char*, int, int, int)       /* Callback */
   );
 
   int (*xPhraseCount)(Fts5Context*);
   int (*xPhraseSize)(Fts5Context*, int iPhrase);
 
   int (*xInstCount)(Fts5Context*, int *pnInst);
   int (*xInst)(Fts5Context*, int iIdx, int *piPhrase, int *piCol, int *piOff);
 
   sqlite3_int64 (*xRowid)(Fts5Context*);
   int (*xColumnText)(Fts5Context*, int iCol, const char **pz, int *pn);
   int (*xColumnSize)(Fts5Context*, int iCol, int *pnToken);
 
   int (*xQueryPhrase)(Fts5Context*, int iPhrase, void *pUserData,
     int(*)(const Fts5ExtensionApi*,Fts5Context*,void*)
   );
   int (*xSetAuxdata)(Fts5Context*, void *pAux, void(*xDelete)(void*));
   void *(*xGetAuxdata)(Fts5Context*, int bClear);
 
   int (*xPhraseFirst)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*, int*);
   void (*xPhraseNext)(Fts5Context*, Fts5PhraseIter*, int *piCol, int *piOff);
 
   int (*xPhraseFirstColumn)(Fts5Context*, int iPhrase, Fts5PhraseIter*, int*);
   void (*xPhraseNextColumn)(Fts5Context*, Fts5PhraseIter*, int *piCol);
 };
 
 /* 
 ** CUSTOM AUXILIARY FUNCTIONS
 *************************************************************************/
 
 /*************************************************************************
 ** CUSTOM TOKENIZERS
 **
 ** Applications may also register custom tokenizer types. A tokenizer 
 ** is registered by providing fts5 with a populated instance of the 
 ** following structure. All structure methods must be defined, setting
 ** any member of the fts5_tokenizer struct to NULL leads to undefined
 ** behaviour. The structure methods are expected to function as follows:
 **
 ** xCreate:
 **   This function is used to allocate and initialize a tokenizer instance.
 **   A tokenizer instance is required to actually tokenize text.
 **
 **   The first argument passed to this function is a copy of the (void*)
 **   pointer provided by the application when the fts5_tokenizer object
 **   was registered with FTS5 (the third argument to xCreateTokenizer()). 
 **   The second and third arguments are an array of nul-terminated strings
 **   containing the tokenizer arguments, if any, specified following the
 **   tokenizer name as part of the CREATE VIRTUAL TABLE statement used
 **   to create the FTS5 table.
 **
 **   The final argument is an output variable. If successful, (*ppOut) 
 **   should be set to point to the new tokenizer handle and SQLITE_OK
 **   returned. If an error occurs, some value other than SQLITE_OK should
 **   be returned. In this case, fts5 assumes that the final value of *ppOut 
 **   is undefined.
 **
 ** xDelete:
 **   This function is invoked to delete a tokenizer handle previously
 **   allocated using xCreate(). Fts5 guarantees that this function will
 **   be invoked exactly once for each successful call to xCreate().
 **
 ** xTokenize:
 **   This function is expected to tokenize the nText byte string indicated 
 **   by argument pText. pText may or may not be nul-terminated. The first
 **   argument passed to this function is a pointer to an Fts5Tokenizer object
 **   returned by an earlier call to xCreate().
 **
 **   The second argument indicates the reason that FTS5 is requesting
 **   tokenization of the supplied text. This is always one of the following
 **   four values:
 **
 **   <ul><li> <b>FTS5_TOKENIZE_DOCUMENT</b> - A document is being inserted into
 **            or removed from the FTS table. The tokenizer is being invoked to
 **            determine the set of tokens to add to (or delete from) the
 **            FTS index.
 **
 **       <li> <b>FTS5_TOKENIZE_QUERY</b> - A MATCH query is being executed 
 **            against the FTS index. The tokenizer is being called to tokenize 
 **            a bareword or quoted string specified as part of the query.
 **
 **       <li> <b>(FTS5_TOKENIZE_QUERY | FTS5_TOKENIZE_PREFIX)</b> - Same as
 **            FTS5_TOKENIZE_QUERY, except that the bareword or quoted string is
 **            followed by a "*" character, indicating that the last token
 **            returned by the tokenizer will be treated as a token prefix.
 **
 **       <li> <b>FTS5_TOKENIZE_AUX</b> - The tokenizer is being invoked to 
 **            satisfy an fts5_api.xTokenize() request made by an auxiliary
 **            function. Or an fts5_api.xColumnSize() request made by the same
 **            on a columnsize=0 database.  
 **   </ul>
 **
 **   For each token in the input string, the supplied callback xToken() must
 **   be invoked. The first argument to it should be a copy of the pointer
 **   passed as the second argument to xTokenize(). The third and fourth
 **   arguments are a pointer to a buffer containing the token text, and the
 **   size of the token in bytes. The 4th and 5th arguments are the byte offsets
 **   of the first byte of and first byte immediately following the text from
 **   which the token is derived within the input.
 **
 **   The second argument passed to the xToken() callback ("tflags") should
 **   normally be set to 0. The exception is if the tokenizer supports 
 **   synonyms. In this case see the discussion below for details.
 **
 **   FTS5 assumes the xToken() callback is invoked for each token in the 
 **   order that they occur within the input text.
 **
 **   If an xToken() callback returns any value other than SQLITE_OK, then
 **   the tokenization should be abandoned and the xTokenize() method should
 **   immediately return a copy of the xToken() return value. Or, if the
 **   input buffer is exhausted, xTokenize() should return SQLITE_OK. Finally,
 **   if an error occurs with the xTokenize() implementation itself, it
 **   may abandon the tokenization and return any error code other than
 **   SQLITE_OK or SQLITE_DONE.
 **
 ** SYNONYM SUPPORT
 **
 **   Custom tokenizers may also support synonyms. Consider a case in which a
 **   user wishes to query for a phrase such as "first place". Using the 
 **   built-in tokenizers, the FTS5 query 'first + place' will match instances
 **   of "first place" within the document set, but not alternative forms
 **   such as "1st place". In some applications, it would be better to match
 **   all instances of "first place" or "1st place" regardless of which form
 **   the user specified in the MATCH query text.
 **
 **   There are several ways to approach this in FTS5:
 **
 **   <ol><li> By mapping all synonyms to a single token. In this case, the 
 **            In the above example, this means that the tokenizer returns the
 **            same token for inputs "first" and "1st". Say that token is in
 **            fact "first", so that when the user inserts the document "I won
 **            1st place" entries are added to the index for tokens "i", "won",
 **            "first" and "place". If the user then queries for '1st + place',
 **            the tokenizer substitutes "first" for "1st" and the query works
 **            as expected.
 **
 **       <li> By adding multiple synonyms for a single term to the FTS index.
 **            In this case, when tokenizing query text, the tokenizer may 
 **            provide multiple synonyms for a single term within the document.
 **            FTS5 then queries the index for each synonym individually. For
 **            example, faced with the query:
 **
 **   <codeblock>
 **     ... MATCH 'first place'</codeblock>
 **
 **            the tokenizer offers both "1st" and "first" as synonyms for the
 **            first token in the MATCH query and FTS5 effectively runs a query 
 **            similar to:
 **
 **   <codeblock>
 **     ... MATCH '(first OR 1st) place'</codeblock>
 **
 **            except that, for the purposes of auxiliary functions, the query
 **            still appears to contain just two phrases - "(first OR 1st)" 
 **            being treated as a single phrase.
 **
 **       <li> By adding multiple synonyms for a single term to the FTS index.
 **            Using this method, when tokenizing document text, the tokenizer
 **            provides multiple synonyms for each token. So that when a 
 **            document such as "I won first place" is tokenized, entries are
 **            added to the FTS index for "i", "won", "first", "1st" and
 **            "place".
 **
 **            This way, even if the tokenizer does not provide synonyms
 **            when tokenizing query text (it should not - to do would be
 **            inefficient), it doesn't matter if the user queries for 
 **            'first + place' or '1st + place', as there are entires in the
 **            FTS index corresponding to both forms of the first token.
 **   </ol>
 **
 **   Whether it is parsing document or query text, any call to xToken that
 **   specifies a <i>tflags</i> argument with the FTS5_TOKEN_COLOCATED bit
 **   is considered to supply a synonym for the previous token. For example,
 **   when parsing the document "I won first place", a tokenizer that supports
 **   synonyms would call xToken() 5 times, as follows:
 **
 **   <codeblock>
 **       xToken(pCtx, 0, "i",                      1,  0,  1);
 **       xToken(pCtx, 0, "won",                    3,  2,  5);
 **       xToken(pCtx, 0, "first",                  5,  6, 11);
 **       xToken(pCtx, FTS5_TOKEN_COLOCATED, "1st", 3,  6, 11);
 **       xToken(pCtx, 0, "place",                  5, 12, 17);
 **</codeblock>
 **
 **   It is an error to specify the FTS5_TOKEN_COLOCATED flag the first time
 **   xToken() is called. Multiple synonyms may be specified for a single token
 **   by making multiple calls to xToken(FTS5_TOKEN_COLOCATED) in sequence. 
 **   There is no limit to the number of synonyms that may be provided for a
 **   single token.
 **
 **   In many cases, method (1) above is the best approach. It does not add 
 **   extra data to the FTS index or require FTS5 to query for multiple terms,
 **   so it is efficient in terms of disk space and query speed. However, it
 **   does not support prefix queries very well. If, as suggested above, the
 **   token "first" is subsituted for "1st" by the tokenizer, then the query:
 **
 **   <codeblock>
 **     ... MATCH '1s*'</codeblock>
 **
 **   will not match documents that contain the token "1st" (as the tokenizer
 **   will probably not map "1s" to any prefix of "first").
 **
 **   For full prefix support, method (3) may be preferred. In this case, 
 **   because the index contains entries for both "first" and "1st", prefix
 **   queries such as 'fi*' or '1s*' will match correctly. However, because
 **   extra entries are added to the FTS index, this method uses more space
 **   within the database.
 **
 **   Method (2) offers a midpoint between (1) and (3). Using this method,
 **   a query such as '1s*' will match documents that contain the literal 
 **   token "1st", but not "first" (assuming the tokenizer is not able to
 **   provide synonyms for prefixes). However, a non-prefix query like '1st'
 **   will match against "1st" and "first". This method does not require
 **   extra disk space, as no extra entries are added to the FTS index. 
 **   On the other hand, it may require more CPU cycles to run MATCH queries,
 **   as separate queries of the FTS index are required for each synonym.
 **
 **   When using methods (2) or (3), it is important that the tokenizer only
 **   provide synonyms when tokenizing document text (method (2)) or query
 **   text (method (3)), not both. Doing so will not cause any errors, but is
 **   inefficient.
 */
 typedef struct Fts5Tokenizer Fts5Tokenizer;
 typedef struct fts5_tokenizer fts5_tokenizer;
 struct fts5_tokenizer {
   int (*xCreate)(void*, const char **azArg, int nArg, Fts5Tokenizer **ppOut);
   void (*xDelete)(Fts5Tokenizer*);
   int (*xTokenize)(Fts5Tokenizer*, 
       void *pCtx,
       int flags,            /* Mask of FTS5_TOKENIZE_* flags */
       const char *pText, int nText, 
       int (*xToken)(
         void *pCtx,         /* Copy of 2nd argument to xTokenize() */
         int tflags,         /* Mask of FTS5_TOKEN_* flags */
         const char *pToken, /* Pointer to buffer containing token */
         int nToken,         /* Size of token in bytes */
         int iStart,         /* Byte offset of token within input text */
         int iEnd            /* Byte offset of end of token within input text */
       )
   );
 };
 
 /* Flags that may be passed as the third argument to xTokenize() */
 #define FTS5_TOKENIZE_QUERY     0x0001
 #define FTS5_TOKENIZE_PREFIX    0x0002
 #define FTS5_TOKENIZE_DOCUMENT  0x0004
 #define FTS5_TOKENIZE_AUX       0x0008
 
 /* Flags that may be passed by the tokenizer implementation back to FTS5
 ** as the third argument to the supplied xToken callback. */
 #define FTS5_TOKEN_COLOCATED    0x0001      /* Same position as prev. token */
 
 /*
 ** END OF CUSTOM TOKENIZERS
 *************************************************************************/
 
 /*************************************************************************
 ** FTS5 EXTENSION REGISTRATION API
 */
 typedef struct fts5_api fts5_api;
 struct fts5_api {
   int iVersion;                   /* Currently always set to 2 */
 
   /* Create a new tokenizer */
   int (*xCreateTokenizer)(
     fts5_api *pApi,
     const char *zName,
     void *pContext,
     fts5_tokenizer *pTokenizer,
     void (*xDestroy)(void*)
   );
 
   /* Find an existing tokenizer */
   int (*xFindTokenizer)(
     fts5_api *pApi,
     const char *zName,
     void **ppContext,
     fts5_tokenizer *pTokenizer
   );
 
   /* Create a new auxiliary function */
   int (*xCreateFunction)(
     fts5_api *pApi,
     const char *zName,
     void *pContext,
     fts5_extension_function xFunction,
     void (*xDestroy)(void*)
   );
 };
 
 /*
 ** END OF REGISTRATION API
 *************************************************************************/
 
 #ifdef __cplusplus
 }  /* end of the 'extern "C"' block */
 #endif
 
 #endif /* _FTS5_H */
 
 /******** End of fts5.h *********/