The Tor Browser / file revision

 /*

 ** 2001 September 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 suppose 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

 /*

 ** Add the ability to override 'extern'

 */

 #ifndef SQLITE_EXTERN

 # define SQLITE_EXTERN extern

 #endif

 #ifndef SQLITE_API

 # define SQLITE_API

 #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 support 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, 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 an SHA1

 ** hash of the entire source tree.

 **

 ** See also: [sqlite3_libversion()],

 ** [sqlite3_libversion_number()], [sqlite3_sourceid()],

 ** [sqlite_version()] and [sqlite_source_id()].

 */

 #define SQLITE_VERSION        "3.8.4.2"

 #define SQLITE_VERSION_NUMBER 3008004

 #define SQLITE_SOURCE_ID      "2014-03-26 18:51:19 02ea166372bdb2ef9d8dfbb05e78a97609673a8e"

 /*

 ** 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 insure that the application is

 ** compiled with matching library and header files.

 **

 ** <blockquote><pre>

 ** assert( sqlite3_libversion_number()==SQLITE_VERSION_NUMBER );

 ** assert( strcmp(sqlite3_sourceid(),SQLITE_SOURCE_ID)==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.

 **

 ** 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_MUTEX].  ^(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;

   typedef unsigned SQLITE_INT64_TYPE sqlite_uint64;

 #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

 **

 ** ^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 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 but 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

 **

 ** 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

 ** 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 insure 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: SQLITE_OK {error code} {error codes}

 ** KEYWORDS: {result code} {result codes}

 **

 ** 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: [SQLITE_IOERR_READ | extended result codes],

 ** [sqlite3_vtab_on_conflict()] [SQLITE_ROLLBACK | result codes].

 */

 #define SQLITE_OK           0   /* Successful result */

 /* beginning-of-error-codes */

 #define SQLITE_ERROR        1   /* SQL error or missing database */

 #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   /* Database is empty */

 #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   /* Auxiliary database format error */

 #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 error code} {extended error codes}

 ** KEYWORDS: {extended result code} {extended result codes}

 **

 ** In its default configuration, SQLite API routines return one of 26 integer

 ** [SQLITE_OK | 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 and later) include

 ** support for additional result codes that provide more detailed information

 ** about errors. The extended result codes are enabled or disabled

 ** on a per database connection basis using the

 ** [sqlite3_extended_result_codes()] API.

 **

 ** Some of the available extended result codes are listed here.

 ** One may expect the number of extended result codes will increase

 ** over time.  Software that uses extended result codes should expect

 ** to see new result codes in future releases of SQLite.

 **

 ** The SQLITE_OK result code will never be extended.  It will always

 ** be exactly zero.

 */

 #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_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_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))

 /*

 ** 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 indicate that a file cannot be deleted when open.

 */

 #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

 /*

 ** 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 [SQLITE_FCNTL_LOCKSTATE | 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]

 ** </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

 **

 ** These integer constants are opcodes for the xFileControl method

 ** of the [sqlite3_io_methods] object and for the [sqlite3_file_control()]

 ** interface.

 **

 ** 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 only needs to be supported when SQLITE_TEST

 ** is defined.

 ** <ul>

 ** <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 the [sqlite3_file_control()] documentation for

 ** additional information.

 **

 ** <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 i 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_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 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.

 **

 ** </ul>

 */

 #define SQLITE_FCNTL_LOCKSTATE               1

 #define SQLITE_GET_LOCKPROXYFILE             2

 #define SQLITE_SET_LOCKPROXYFILE             3

 #define SQLITE_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

 /*

 ** 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: 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 value of the iVersion field is initially 1 but may be larger in

 ** future versions of SQLite.  Additional fields may be appended to this

 ** object when the iVersion value is increased.  Note that the structure

 ** of the sqlite3_vfs object changes in the transaction between

 ** SQLite version 3.5.9 and 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 figure 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 no 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.

 **

 ** The sqlite3_config() interface is not threadsafe.  The application

 ** must insure that no other SQLite interfaces are invoked by other

 ** threads while sqlite3_config() is running.  Furthermore, sqlite3_config()

 ** 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

 **

 ** 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> ^(This 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> ^(This 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_MEMSTATUS]] <dt>SQLITE_CONFIG_MEMSTATUS</dt>

 ** <dd> ^This 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_status()]

 **   </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> ^This option specifies a static memory buffer that SQLite can use for

 ** scratch memory.  There are three arguments:  A pointer an 8-byte

 ** aligned memory buffer from which the scratch allocations will be

 ** drawn, the size of each scratch allocation (sz),

 ** and the maximum number of scratch allocations (N).  The sz

 ** argument must be a multiple of 16.

 ** The first argument must be a pointer to an 8-byte aligned buffer

 ** of at least sz*N bytes of memory.

 ** ^SQLite will use no more than two scratch buffers per thread.  So

 ** N should be set to twice the expected maximum number of threads.

 ** ^SQLite will never require a scratch buffer that is more than 6

 ** times the database page size. ^If SQLite needs needs additional

 ** scratch memory beyond what is provided by this configuration option, then 

 ** [sqlite3_malloc()] will be used to obtain the memory needed.</dd>

 **

 ** [[SQLITE_CONFIG_PAGECACHE]] <dt>SQLITE_CONFIG_PAGECACHE</dt>

 ** <dd> ^This option specifies a static memory buffer that SQLite can use for

 ** the database page cache with the default page cache implementation.  

 ** This configuration should not be used if an application-define page

 ** cache implementation is loaded using the SQLITE_CONFIG_PCACHE2 option.

 ** There are three arguments to this option: A pointer to 8-byte aligned

 ** memory, the size of each page buffer (sz), and the number of pages (N).

 ** The sz argument should be the size of the largest database page

 ** (a power of two between 512 and 32768) plus a little extra for each

 ** page header.  ^The page header size is 20 to 40 bytes depending on

 ** the host architecture.  ^It is harmless, apart from the wasted memory,

 ** to make sz a little too large.  The first

 ** argument should point to an allocation of at least sz*N bytes of memory.

 ** ^SQLite will use the memory provided by the first argument to satisfy its

 ** memory needs for the first N pages that it adds to cache.  ^If additional

 ** page cache memory is needed beyond what is provided by this option, then

 ** SQLite goes to [sqlite3_malloc()] for the additional storage space.

 ** The pointer in the first argument must

 ** be aligned to an 8-byte boundary or subsequent behavior of SQLite

 ** will be undefined.</dd>

 **

 ** [[SQLITE_CONFIG_HEAP]] <dt>SQLITE_CONFIG_HEAP</dt>

 ** <dd> ^This 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_SCRATCH] and [SQLITE_CONFIG_PAGECACHE].

 ** There are three arguments: 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 and either [SQLITE_ENABLE_MEMSYS3] or

 ** [SQLITE_ENABLE_MEMSYS5] are defined, 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> ^(This 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> ^(This 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> ^(This option takes two arguments that determine the default

 ** memory allocation for the lookaside memory allocator 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.)^  ^(This option sets the

 ** <i>default</i> lookaside size. The [SQLITE_DBCONFIG_LOOKASIDE]

 ** verb 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> ^(This 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

 ** object and uses it for page cache memory allocations.</dd>

 **

 ** [[SQLITE_CONFIG_GETPCACHE2]] <dt>SQLITE_CONFIG_GETPCACHE2</dt>

 ** <dd> ^(This 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>^(This 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>^This 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

 ** cannot be changed at run-time.  Nor may the maximum allowed mmap size

 ** 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>^This 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.

 ** </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  /* void*, int sz, int N */

 #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 */

 /*

 ** 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>

 **

 ** </dl>

 */

 #define SQLITE_DBCONFIG_LOOKASIDE       1001  /* void* int int */

 #define SQLITE_DBCONFIG_ENABLE_FKEY     1002  /* int int* */

 #define SQLITE_DBCONFIG_ENABLE_TRIGGER  1003  /* int int* */

 /*

 ** CAPI3REF: Enable Or Disable Extended Result Codes

 **

 ** ^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

 **

 ** ^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 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.

 **

 ** ^(If an [INSERT] occurs within a trigger or within a [virtual table]

 ** method, then this routine will return the [rowid] of the inserted

 ** row as long as the trigger or virtual table method is running.

 ** But once the trigger or virtual table method ends, the value returned 

 ** by this routine reverts to what it was before the trigger or virtual

 ** table method began.)^

 **

 ** ^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: Count The Number Of Rows Modified

 **

 ** ^This function returns the number of database rows that were changed

 ** or inserted or deleted by the most recently completed SQL statement

 ** on the [database connection] specified by the first parameter.

 ** ^(Only changes that are directly specified by the [INSERT], [UPDATE],

 ** or [DELETE] statement are counted.  Auxiliary changes caused by

 ** triggers or [foreign key actions] are not counted.)^ Use the

 ** [sqlite3_total_changes()] function to find the total number of changes

 ** including changes caused by triggers and foreign key actions.

 **

 ** ^Changes to a view that are simulated by an [INSTEAD OF trigger]

 ** are not counted.  Only real table changes are counted.

 **

 ** ^(A "row change" is a change to a single row of a single table

 ** caused by an INSERT, DELETE, or UPDATE statement.  Rows that

 ** are changed as side effects of [REPLACE] constraint resolution,

 ** rollback, ABORT processing, [DROP TABLE], or by any other

 ** mechanisms do not count as direct row changes.)^

 **

 ** A "trigger context" is a scope of execution that begins and

 ** ends with the script of a [CREATE TRIGGER | trigger]. 

 ** Most SQL statements are

 ** evaluated outside of any trigger.  This is the "top level"

 ** trigger context.  If a trigger fires from the top level, a

 ** new trigger context is entered for the duration of that one

 ** trigger.  Subtriggers create subcontexts for their duration.

 **

 ** ^Calling [sqlite3_exec()] or [sqlite3_step()] recursively does

 ** not create a new trigger context.

 **

 ** ^This function returns the number of direct row changes in the

 ** most recent INSERT, UPDATE, or DELETE statement within the same

 ** trigger context.

 **

 ** ^Thus, when called from the top level, this function returns the

 ** number of changes in the most recent INSERT, UPDATE, or DELETE

 ** that also occurred at the top level.  ^(Within the body of a trigger,

 ** the sqlite3_changes() interface can be called to find the number of

 ** changes in the most recently completed INSERT, UPDATE, or DELETE

 ** statement within the body of the same trigger.

 ** However, the number returned does not include changes

 ** caused by subtriggers since those have their own context.)^

 **

 ** 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

 **

 ** ^This function returns the number of row changes caused by [INSERT],

 ** [UPDATE] or [DELETE] statements since the [database connection] was opened.

 ** ^(The count returned by sqlite3_total_changes() includes all changes

 ** from all [CREATE TRIGGER | trigger] contexts and changes made by

 ** [foreign key actions]. However,

 ** the count does not include changes used to implement [REPLACE] constraints,

 ** do rollbacks or ABORT processing, or [DROP TABLE] processing.  The

 ** count does not include rows of views that fire an [INSTEAD OF trigger],

 ** though if the INSTEAD OF trigger makes changes of its own, those changes 

 ** are counted.)^

 ** ^The sqlite3_total_changes() function counts the changes as soon as

 ** the statement that makes them is completed (when the statement handle

 ** is passed to [sqlite3_reset()] or [sqlite3_finalize()]).

 **

 ** 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

 **

 ** ^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.

 **

 ** If the database connection closes while [sqlite3_interrupt()]

 ** is running then bad things will likely happen.

 */

 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

 **

 ** ^This routine sets a callback function that might be invoked whenever

 ** an attempt is made to open a database table that another thread

 ** or process has locked.

 **

 ** ^If the busy callback is NULL, then [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED]

 ** 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 for this locking event.  ^If the

 ** busy callback returns 0, then no additional attempts are made to

 ** access the database and [SQLITE_BUSY] or [SQLITE_IOERR_BLOCKED] is returned.

 ** ^If the callback returns non-zero, then another attempt

 ** is made to open the database for reading 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]

 ** or [SQLITE_IOERR_BLOCKED] 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.

 **

 ** ^The [SQLITE_BUSY] error is converted to [SQLITE_IOERR_BLOCKED]

 ** when SQLite is in the middle of a large transaction where all the

 ** changes will not fit into the in-memory cache.  SQLite will

 ** already hold a RESERVED lock on the database file, but it needs

 ** to promote this lock to EXCLUSIVE so that it can spill cache

 ** pages into the database file without harm to concurrent

 ** readers.  ^If it is unable to promote the lock, then the in-memory

 ** cache will be left in an inconsistent state and so the error

 ** code is promoted from the relatively benign [SQLITE_BUSY] to

 ** the more severe [SQLITE_IOERR_BLOCKED].  ^This error code promotion

 ** forces an automatic rollback of the changes.  See the

 ** <a href="/cvstrac/wiki?p=CorruptionFollowingBusyError">

 ** CorruptionFollowingBusyError</a> wiki page for a discussion of why

 ** this is important.

 **

 ** ^(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()]

 ** will also set or clear the busy handler.

 **

 ** The busy callback should not take any actions which modify the

 ** database connection that invoked the busy handler.  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

 **

 ** ^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] or [SQLITE_IOERR_BLOCKED].

 **

 ** ^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] any any given moment.  If another busy handler

 ** was defined  (using [sqlite3_busy_handler()]) prior to calling

 ** this routine, that other busy handler is cleared.)^

 */

 SQLITE_API int sqlite3_busy_timeout(sqlite3*, int ms);

 /*

 ** CAPI3REF: Convenience Routines For Running Queries

 **

 ** 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[0] = "Name";

 **        azResult[1] = "Age";

 **        azResult[2] = "Alice";

 **        azResult[3] = "43";

 **        azResult[4] = "Bob";

 **        azResult[5] = "28";

 **        azResult[6] = "Cindy";

 **        azResult[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.

 **

 ** ^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", 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 "%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.

 **

 ** ^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() interface attempts to resize a

 ** prior memory allocation to be at least N bytes, where N is the

 ** second parameter.  The memory allocation to be resized is the first

 ** parameter.)^ ^ If the first parameter to sqlite3_realloc()

 ** is a NULL pointer then its behavior is identical to calling

 ** sqlite3_malloc(N) where N is the second parameter to sqlite3_realloc().

 ** ^If the second parameter to sqlite3_realloc() is zero or

 ** negative then the behavior is exactly the same as calling

 ** sqlite3_free(P) where P is the first parameter to sqlite3_realloc().

 ** ^sqlite3_realloc() returns a pointer to a memory allocation

 ** of at least N bytes in size or NULL if sufficient memory is unavailable.

 ** ^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() and the prior allocation is freed.

 ** ^If sqlite3_realloc() returns NULL, then the prior allocation

 ** is not freed.

 **

 ** ^The memory returned by sqlite3_malloc() and sqlite3_realloc()

 ** 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_realloc(void*, int);

 SQLITE_API void sqlite3_free(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.

 ** ^If N is less than one, then P can be a NULL pointer.

 **

 ** ^If this routine has not been previously called or if the previous

 ** call had N less than one, 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 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

 **

 ** ^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_prepare16()] and [sqlite3_prepare16_v2()].  ^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 zero-terminated strings that contain additional

 ** details about the action to be authorized.

 **

 ** ^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.

 ** ^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 [SQLITE_ROLLBACK | return code]

 ** 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

 **

 ** 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 void *sqlite3_trace(sqlite3*, void(*xTrace)(void*,const char*), void*);

 SQLITE_API SQLITE_EXPERIMENTAL void *sqlite3_profile(sqlite3*,

    void(*xProfile)(void*,const char*,sqlite3_uint64), void*);

 /*

 ** CAPI3REF: Query Progress Callbacks

 **

 ** ^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

 **

 ** ^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