SQLite

** 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.
**
** @(#) $Id: sqlite.h.in,v 1.318 2008/05/23 17:21:09 shane Exp $
*/
#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++.

**          SQL statements in the zero-terminated string S within the
**          context of the D [database connection].
**
** {F12102} If the S parameter to [sqlite3_exec(D,S,C,A,E)] is NULL then
**          the actions of the interface shall be the same as if the
**          S parameter where an empty string.
**
** {F12104} The return value of [sqlite3_exec()] shall be [SQLITE_OK] if all
**          SQL statements run successfully and to completion.
**
** {F12105} The return value of [sqlite3_exec()] shall be an appropriate 
**          non-zero [error code] if any SQL statement fails.
**
** {F12107} If one or more of the SQL statements handed to [sqlite3_exec()]
**          return results and the 3rd parameter is not NULL, then

** 
** {F11148} At least szOsFile bytes of memory are allocated by SQLite 
** to hold the  [sqlite3_file] structure passed as the third 
** argument to xOpen.  {END}  The xOpen method does not have to
** allocate the structure; it should just fill it in.
** 
** {F11149} The flags argument to xAccess() may be [SQLITE_ACCESS_EXISTS] 
** to test for the existence of a file,
** or [SQLITE_ACCESS_READWRITE] to test to see
** if a file is readable and writable, or [SQLITE_ACCESS_READ]
** to test to see if a file is at least readable.  {END} The file can be a 
** directory.
** 
** {F11150} SQLite will always allocate at least mxPathname+1 bytes for
** the output buffers for xGetTempname and xFullPathname. {F11151} The exact
** size of the output buffer is also passed as a parameter to both 
** methods. {END} If the output buffer is not large enough, [SQLITE_CANTOPEN]
** should be returned. As 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(), and xCurrentTime() interfaces
** are not strictly a part of the filesystem, but they are
** included in the VFS structure for completeness.

/*
** CAPI3REF: Flags for the xAccess VFS method {F11190}
**
** {F11191} These integer constants can be used as the third parameter to
** the xAccess method of an [sqlite3_vfs] object. {END}  They determine
** what kind of permissions the xAccess method is
** looking for.  {F11192} With [SQLITE_ACCESS_EXISTS], the xAccess method
** simply checks to see if the file exists. {F11193} With
** SQLITE_ACCESS_READWRITE, the xAccess method checks to see
** if the file is both readable and writable.  {F11194} With
** SQLITE_ACCESS_READ the xAccess method
** checks to see if the file is readable.
*/
#define SQLITE_ACCESS_EXISTS    0

**          [sqlite3_changes()] to return zero, regardless of the
**          number of rows originally in the table.
**
** LIMITATIONS:
**
** {U12252} 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.
*/
int sqlite3_changes(sqlite3*);

/*
** CAPI3REF: Total Number Of Rows Modified {F12260}
***
** This function returns the number of row changes caused

**          WHERE clause shall not change the value returned
**          by [sqlite3_total_changes()]
**
** LIMITATIONS:
**
** {U12264} 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.
*/
int sqlite3_total_changes(sqlite3*);

/*
** CAPI3REF: Interrupt A Long-Running Query {F12270}
**
** This function causes any pending database operation to abort and

** {F12311} The [sqlite3_busy_handler()] function replaces the busy handler
**          callback in the database connection identified by the 1st
**          parameter with a new busy handler identified by the 2nd and 3rd
**          parameters.
**
** {F12312} The default busy handler for new database connections is NULL.
**
** {F12314} When two or more database connection share a [sqlite3_enable_shared_cache | common cache],
**          the busy handler for the database connection currently using
**          the cache is invoked when the cache encounters a lock.
**
** {F12316} If a busy handler callback returns zero, then the SQLite
**          interface that provoked the locking event will return
**          [SQLITE_BUSY].
**
** {F12318} SQLite will invokes the busy handler with two arguments which
**          are a copy of the pointer supplied by the 3rd parameter to
**          [sqlite3_busy_handler()] and a count of the number of prior
**          invocations of the busy handler for the same locking event.
**
** LIMITATIONS:
**
** {U12319} A busy handler should not call close the database connection

** The sqlite3_get_table() function evaluates one or more
** semicolon-separated SQL statements in the zero-terminated UTF-8
** string of its 2nd parameter.  It returns a result table to the
** pointer given in its 3rd parameter.
**
** After the calling function has finished using the result, it should 
** pass the pointer to the result table 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

** 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.
**
** 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 null-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.

/*
** CAPI3REF: Memory Allocation Subsystem {F17300}
**
** 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.

**
** 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.
**
** The Windows OS interface layer calls
** 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 are detected, but
** they are reported back as [SQLITE_CANTOPEN] or
** [SQLITE_IOERR] rather than [SQLITE_NOMEM].
**
** INVARIANTS:
**
** {F17303}  The [sqlite3_malloc(N)] interface returns either a pointer to 

**
** {F17318}  The [sqlite3_realloc(P,N)] interface returns either a pointer
**           to a block of checked-out memory of at least N bytes in size
**           that is 8-byte aligned, or a NULL pointer.
**
** {F17321}  When [sqlite3_realloc(P,N)] returns a non-NULL pointer, it first
**           copies the first K bytes of content from P into the newly allocated
**           where K is the lesser of N and the size of the buffer P.
**
** {F17322}  When [sqlite3_realloc(P,N)] returns a non-NULL pointer, it first
**           releases the buffer P.
**
** {F17323}  When [sqlite3_realloc(P,N)] returns NULL, the buffer P is
**           not modified or released.
**

**
** {F17371} The [sqlite3_memory_used()] routine returns the
**          number of bytes of memory currently outstanding 
**          (malloced but not freed).
**
** {F17373} The [sqlite3_memory_highwater()] routine returns the maximum
**          value of [sqlite3_memory_used()] 
**          since the high-water mark was last reset.
**
** {F17374} 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.
** 
** {F17375} 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.
*/
sqlite3_int64 sqlite3_memory_used(void);
sqlite3_int64 sqlite3_memory_highwater(int resetFlag);

/*
** CAPI3REF: Pseudo-Random Number Generator {F17390}
**
** SQLite contains a high-quality pseudo-random number generator (PRNG) used to
** select random ROWIDs when inserting new records into a table that
** already uses the largest possible ROWID.  The PRNG is also used for
** the build-in random() and randomblob() SQL functions.  This interface allows
** applications to access the same PRNG for other purposes.
**
** A call to this routine stores N bytes of randomness into buffer P.
**
** The first time this routine is invoked (either internally or by
** the application) the PRNG is seeded using randomness obtained
** from the xRandomness method of the default [sqlite3_vfs] object.
** On all subsequent invocations, the pseudo-randomness is generated

** 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.
**
** INVARIANTS:
**
** {F12551} The second parameter to an 
**          [sqlite3_set_authorizer | authorizer callback] is always an integer
**          [SQLITE_COPY | authorizer code] that specifies what action
**          is being authorized.
**
** {F12552} The 3rd and 4th parameters to the 
**          [sqlite3_set_authorizer | authorization callback function]
**          will be parameters or NULL depending on which 
**          [SQLITE_COPY | authorizer code] is used as the second parameter.

** 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 callback returns a UTF-8 rendering of the SQL statement text
** as the statement first begins executing.  Additional callbacks occur
** as each triggered subprogram is entered.  The callbacks for triggers
** contain a UTF-8 SQL comment that identifies the trigger.
** 
** 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.
**

**          function each time it is invoked.
**
** {F12915} If a call to [sqlite3_step()] results in fewer than
**          N opcodes being executed,
**          then the progress callback is never invoked. {END}
** 
** {F12916} Every call to [sqlite3_progress_handler()]
**          overwrites any previously registered progress handler.
**
** {F12917} If the progress handler callback is NULL then no progress
**          handler is invoked.
**
** {F12918} If the progress callback returns a result other than 0, then
**          the behavior is a if [sqlite3_interrupt()] had been called.
*/

** UTF-16 in the native byte order if [sqlite3_open16()] is used.
**
** Whether or not an error occurs when it is opened, resources
** associated with the [sqlite3*] handle should be released by passing it
** to [sqlite3_close()] when it is no longer required.
**
** The [sqlite3_open_v2()] interface works like [sqlite3_open()] 
** except that it accepts two additional parameters for additional control
** over the new database connection.  The flags parameter can be
** one of:
**
** <ol>
** <li>  [SQLITE_OPEN_READONLY]
** <li>  [SQLITE_OPEN_READWRITE]
** <li>  [SQLITE_OPEN_READWRITE] | [SQLITE_OPEN_CREATE]

**
** The fourth parameter to sqlite3_open_v2() is the name of the
** [sqlite3_vfs] object that defines the operating system 
** interface that the new database connection should use.  If the
** fourth parameter is a NULL pointer then the default [sqlite3_vfs]
** object is used.
**
** <b>Note to Windows users:</b>  The encoding used for the filename argument
** of [sqlite3_open()] and [sqlite3_open_v2()] must be UTF-8, not whatever
** codepage is currently defined.  Filenames containing international
** characters must be converted to UTF-8 prior to passing them into
** [sqlite3_open()] or [sqlite3_open_v2()].
**
** INVARIANTS:
**

** {F12717} If the filename argument to [sqlite3_open()], [sqlite3_open16()],
**          or [sqlite3_open_v2()] is ":memory:", then an private,
**          ephemeral, in-memory database is created for the connection.
**          <todo>Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE required
**          in sqlite3_open_v2()?</todo>
**
** {F12719} If the filename is NULL or an empty string, then a private,
**          ephemeral on-disk database will be created.
**          <todo>Is SQLITE_OPEN_CREATE|SQLITE_OPEN_READWRITE required
**          in sqlite3_open_v2()?</todo>
**
** {F12721} The [database connection] created by 
**          [sqlite3_open_v2(F,D,G,V)] will use the
**          [sqlite3_vfs] object identified by the V parameter, or
**          the default [sqlite3_vfs] object is V is a NULL pointer.

const char *sqlite3_errmsg(sqlite3*);
const void *sqlite3_errmsg16(sqlite3*);

/*
** CAPI3REF: SQL Statement Object {F13000}
** KEYWORDS: {prepared statement} {prepared statements}
**
** An instance of this object represents a single SQL statement.  This
** object is variously known as a "prepared statement" or a 
** "compiled SQL statement" or simply as a "statement".
** 
** The life of a statement object goes something like this:
**
** <ol>
** <li> Create the object using [sqlite3_prepare_v2()] or a related

** Attempts to increase a limit above its hard upper bound are
** silently truncated to the hard upper limit.
**
** Run time limits are intended for use in applications that manage
** both their own internal database and also databases that are controlled
** by untrusted external sources.  An example application might be a
** webbrowser that has its own databases for storing history and
** separate databases controlled by JavaScript applications downloaded
** off the internet.  The internal databases can be given the
** large, default limits.  Databases managed by external sources can
** be given much smaller limits designed to prevent a denial of service
** attach.  Developers might also want to use the [sqlite3_set_authorizer()]
** interface to further control untrusted SQL.  The size of the database
** created by an untrusted script can be contained using the
** [max_page_count] [PRAGMA].
**
** This interface is currently considered experimental and is subject
** to change or removal without prior notice.
**
** INVARIANTS:
**
** {F12762} A successful call to [sqlite3_limit(D,C,V)] where V is
**          positive changes the
**          limit on the size of construct C in [database connection] D
**          to the lesser of V and the hard upper bound on the size
**          of C that is set at compile-time.
**
** {F12766} A successful call to [sqlite3_limit(D,C,V)] where V is negative
**          leaves the state of [database connection] D unchanged.
**
** {F12769} A successful call to [sqlite3_limit(D,C,V)] returns the
**          value of the limit on the size of construct C in

** the nByte-th byte, whichever comes first. If the caller knows
** that the supplied string is nul-terminated, then there is a small
** performance advantage to be had by passing an nByte parameter that 
** is equal to the number of bytes in the input string <i>including</i> 
** the nul-terminator bytes.{END}
**
** *pzTail is made to point to the first byte past the end of the
** first SQL statement in zSql.  These routines only compile the first
** statement in zSql, so *pzTail is left pointing to what remains
** uncompiled.
**
** *ppStmt is left pointing to a compiled [prepared statement] that can be
** executed using [sqlite3_step()].  Or if there is an error, *ppStmt is
** set to NULL.  If the input text contains no SQL (if the input
** is and empty string or a comment) then *ppStmt is set to NULL.

  sqlite3_stmt **ppStmt,  /* OUT: Statement handle */
  const void **pzTail     /* OUT: Pointer to unused portion of zSql */
);

/*
** CAPIREF: Retrieving Statement SQL {F13100}
**
** This interface  can be used to retrieve a saved copy of the original
** SQL text used to create a [prepared statement].
**
** INVARIANTS:
**
** {F13101} If the [prepared statement] passed as 
**          the an argument to [sqlite3_sql()] was compiled
**          compiled using either [sqlite3_prepare_v2()] or

** The terms "protected" and "unprotected" refer to whether or not
** a mutex is held.  A internal mutex is held for a protected
** sqlite3_value object but no mutex is held for an unprotected
** sqlite3_value object.  If SQLite is compiled to be single-threaded
** (with SQLITE_THREADSAFE=0 and with [sqlite3_threadsafe()] returning 0)
** then there is no distinction between
** protected and unprotected sqlite3_value objects and they can be
** used interchangeable.  However, for maximum code portability it
** is recommended that applications make the distinction between
** between protected and unprotected sqlite3_value objects even if
** they are single threaded.
**
** The sqlite3_value objects that are passed as parameters into the
** implementation of application-defined SQL functions are protected.
** The sqlite3_value object returned by

** The third argument is the value to bind to the parameter.
**
** In those
** routines that have a fourth argument, its value is the number of bytes
** in the parameter.  To be clear: the value is the number of <u>bytes</u>
** in the value, not the number of characters. 
** If the fourth parameter is negative, the length of the string is
** the number of bytes up to the first zero terminator.
**
** The fifth argument to sqlite3_bind_blob(), sqlite3_bind_text(), and
** sqlite3_bind_text16() is a destructor used to dispose of the BLOB or
** string after SQLite has finished with it. If the fifth argument is
** the special value [SQLITE_STATIC], then SQLite assumes that the
** information is in static, unmanaged space and does not need to be freed.
** If the fifth argument has the value [SQLITE_TRANSIENT], then
** SQLite makes its own private copy of the data immediately, before
** the sqlite3_bind_*() routine returns.
**
** The sqlite3_bind_zeroblob() routine binds a BLOB of length N that
** is filled with zeros.  A zeroblob uses a fixed amount of memory
** (just an integer to hold it size) while it is being processed.
** Zeroblobs are intended to serve as placeholders for BLOBs whose
** content is later written using 
** [sqlite3_blob_open | increment BLOB I/O] routines. A negative
** value for the zeroblob results in a zero-length BLOB.
**
** The sqlite3_bind_*() routines must be called after
** [sqlite3_prepare_v2()] (and its variants) or [sqlite3_reset()] and
** before [sqlite3_step()].
** Bindings are not cleared by the [sqlite3_reset()] routine.
** Unbound parameters are interpreted as NULL.
**
** These routines return [SQLITE_OK] on success or an error code if
** anything goes wrong.  [SQLITE_RANGE] is returned if the parameter
** index is out of range.  [SQLITE_NOMEM] is returned if malloc() fails.
** [SQLITE_MISUSE] might be returned if these routines are called on a
** virtual machine that is the wrong state or which has already been finalized.
** Detection of misuse is unreliable.  Applications should not depend
** on SQLITE_MISUSE returns.  SQLITE_MISUSE is intended to indicate a
** a logic error in the application.  Future versions of SQLite might
** panic rather than return SQLITE_MISUSE.
**

** {F13512} The index of an "?" SQL parameter is one larger than the
**          largest index of SQL parameter to the left, or 1 if
**          the "?" is the leftmost SQL parameter.
**
** {F13515} The index of an "?NNN" SQL parameter is the integer NNN.
**
** {F13518} The index of an ":VVV", "$VVV", or "@VVV" SQL parameter is
**          the same as the index of leftmost occurrences of the same
**          parameter, or one more than the largest index over all
**          parameters to the left if this is the first occurrence
**          of this parameter, or 1 if this is the leftmost parameter.
**
** {F13521} The [sqlite3_prepare | SQL statement compiler] fail with
**          an [SQLITE_RANGE] error if the index of an SQL parameter
**          is less than 1 or greater than SQLITE_MAX_VARIABLE_NUMBER.
**
** {F13524} Calls to [sqlite3_bind_text | sqlite3_bind(S,N,V,...)]

/*
** CAPI3REF: Number Of SQL Parameters {F13600}
**
** This routine can be used to find the number of SQL parameters
** in a prepared statement.  SQL parameters are tokens of the
** form "?", "?NNN", ":AAA", "$AAA", or "@AAA" that serve as
** placeholders for values that are [sqlite3_bind_blob | bound]
** to the parameters at a later time.
**
** This routine actually returns the index of the largest parameter.
** For all forms except ?NNN, this will correspond to the number of
** unique parameters.  If parameters of the ?NNN are used, there may
** be gaps in the list.
**

**          interface returns the name
**          of the Nth column (where 0 is the left-most column) for the
**          result set of [prepared statement] S as a
**          zero-terminated UTF-16 string in the native byte order.
**
** {F13724} The [sqlite3_column_name()] and [sqlite3_column_name16()]
**          interfaces return a NULL pointer if they are unable to
**          allocate memory to hold their normal return strings.
**
** {F13725} If the N parameter to [sqlite3_column_name(S,N)] or
**          [sqlite3_column_name16(S,N)] is out of range, then the
**          interfaces return a NULL pointer.
** 
** {F13726} The strings returned by [sqlite3_column_name(S,N)] and
**          [sqlite3_column_name16(S,N)] are valid until the next
**          call to either routine with the same S and N parameters
**          or until [sqlite3_finalize(S)] is called.
**
** {F13727} When a result column of a [SELECT] statement contains
**          an AS clause, the name of that column is the identifier
**          to the right of the AS keyword.
*/
const char *sqlite3_column_name(sqlite3_stmt*, int N);
const void *sqlite3_column_name16(sqlite3_stmt*, int N);

/*
** CAPI3REF: Source Of Data In A Query Result {F13740}

** undefined.
**
** INVARIANTS:
**
** {F13741} The [sqlite3_column_database_name(S,N)] interface returns either
**          the UTF-8 zero-terminated name of the database from which the 
**          Nth result column of [prepared statement] S 
**          is extracted, or NULL if the Nth column of S is a
**          general expression or if unable to allocate memory
**          to store the name.
**          
** {F13742} The [sqlite3_column_database_name16(S,N)] interface returns either
**          the UTF-16 native byte order
**          zero-terminated name of the database from which the 
**          Nth result column of [prepared statement] S 
**          is extracted, or NULL if the Nth column of S is a
**          general expression or if unable to allocate memory
**          to store the name.
**          
** {F13743} The [sqlite3_column_table_name(S,N)] interface returns either
**          the UTF-8 zero-terminated name of the table from which the 
**          Nth result column of [prepared statement] S 
**          is extracted, or NULL if the Nth column of S is a
**          general expression or if unable to allocate memory
**          to store the name.
**          
** {F13744} The [sqlite3_column_table_name16(S,N)] interface returns either
**          the UTF-16 native byte order
**          zero-terminated name of the table from which the 
**          Nth result column of [prepared statement] S 
**          is extracted, or NULL if the Nth column of S is a
**          general expression or if unable to allocate memory
**          to store the name.
**          
** {F13745} The [sqlite3_column_origin_name(S,N)] interface returns either
**          the UTF-8 zero-terminated name of the table column from which the 
**          Nth result column of [prepared statement] S 
**          is extracted, or NULL if the Nth column of S is a
**          general expression or if unable to allocate memory
**          to store the name.
**          
** {F13746} The [sqlite3_column_origin_name16(S,N)] interface returns either
**          the UTF-16 native byte order
**          zero-terminated name of the table column from which the 
**          Nth result column of [prepared statement] S 
**          is extracted, or NULL if the Nth column of S is a
**          general expression or if unable to allocate memory
**          to store the name.
**          
** {F13748} The return values from
**          [sqlite3_column_database_name|column metadata interfaces]
**          are valid
**          for the lifetime of the [prepared statement]

**
** {F15306}  When a call to [sqlite3_step(S)] stops because it is ready
**           to return another row of the result set, it returns
**           [SQLITE_ROW].
**
** {F15308}  If a call to [sqlite3_step(S)] encounters an
**           [sqlite3_interrupt|interrupt] or a run-time error,
**           it returns an appropriate error code that is not one of
**           [SQLITE_OK], [SQLITE_ROW], or [SQLITE_DONE].
**
** {F15310}  If an [sqlite3_interrupt|interrupt] or run-time error
**           occurs during a call to [sqlite3_step(S)]
**           for a [prepared statement] S created using
**           legacy interfaces [sqlite3_prepare()] or
**           [sqlite3_prepare16()] then the function returns either

** <tr><td>  BLOB    <td>  FLOAT    <td> Convert to TEXT then use atof()
** <tr><td>  BLOB    <td>   TEXT    <td> Add a zero terminator if needed
** </table>
** </blockquote>
**
** The table above makes reference to standard C library functions atoi()
** and atof().  SQLite does not really use these functions.  It has its
** own equivalent internal routines.  The atoi() and atof() names are
** used in the table for brevity and because they are familiar to most
** C programmers.
**
** Note that when type conversions occur, pointers returned by prior
** calls to sqlite3_column_blob(), sqlite3_column_text(), and/or
** sqlite3_column_text16() may be invalidated. 
** Type conversions and pointer invalidations might occur

** The seventh, eighth and ninth parameters, xFunc, xStep and xFinal, are
** pointers to C-language functions that implement the SQL
** function or aggregate. A scalar SQL function requires an implementation of
** the xFunc callback only, NULL pointers should be passed as the xStep
** and xFinal parameters. An aggregate SQL function requires an implementation
** of xStep and xFinal and NULL should be passed for xFunc. To delete an
** existing SQL function or aggregate, pass NULL for all three function
** callbacks.
**
** It is permitted to register multiple implementations of the same
** functions with the same name but with either differing numbers of
** arguments or differing preferred text encodings.  SQLite will use
** the implementation most closely matches the way in which the
** SQL function is used.
**
** INVARIANTS:
**
** {F16103} The [sqlite3_create_function16()] interface behaves exactly
**          like [sqlite3_create_function()] in every way except that it
**          interprets the zFunctionName argument as
**          zero-terminated UTF-16 native byte order instead of as a
**          zero-terminated UTF-8.
**
** {F16106} A successful invocation of
**          the [sqlite3_create_function(D,X,N,E,...)] interface registers
**          or replaces callback functions in [database connection] D
**          used to implement the SQL function named X with N parameters
**          and having a preferred text encoding of E.
**
** {F16109} A successful call to [sqlite3_create_function(D,X,N,E,P,F,S,L)]
**          replaces the P, F, S, and L values from any prior calls with
**          the same D, X, N, and E values.
**
** {F16112} The [sqlite3_create_function(D,X,...)] interface fails with
**          a return code of [SQLITE_ERROR] if the SQL function name X is

** These routines work only with [protected sqlite3_value] objects.
** Any attempt to use these routines on an [unprotected sqlite3_value]
** object results in undefined behavior.
**
** These routines work just like the corresponding 
** [sqlite3_column_blob | sqlite3_column_* routines] except that 
** these routines take a single [protected sqlite3_value] object pointer
** instead of a [sqlite3_stmt*] pointer and an integer column number.
**
** The sqlite3_value_text16() interface extracts a UTF16 string
** in the native byte-order of the host machine.  The
** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
** extract UTF16 strings as big-endian and little-endian respectively.
**
** The sqlite3_value_numeric_type() interface attempts to apply

** the aggregate SQL function is running.
**
** INVARIANTS:
**
** {F16211} The first invocation of [sqlite3_aggregate_context(C,N)] for
**          a particular instance of an aggregate function (for a particular
**          context C) causes SQLite to allocation N bytes of memory,
**          zero that memory, and return a pointer to the allocated
**          memory.
**
** {F16213} If a memory allocation error occurs during
**          [sqlite3_aggregate_context(C,N)] then the function returns 0.
**
** {F16215} Second and subsequent invocations of
**          [sqlite3_aggregate_context(C,N)] for the same context pointer C

void *sqlite3_aggregate_context(sqlite3_context*, int nBytes);

/*
** CAPI3REF: User Data For Functions {F16240}
**
** The sqlite3_user_data() interface returns a copy of
** the pointer that was the pUserData parameter (the 5th parameter)
** of the [sqlite3_create_function()]
** and [sqlite3_create_function16()] routines that originally
** registered the application defined function. {END}
**
** This routine must be called from the same thread in which
** the application-defined function is running.
**
** INVARIANTS:

void *sqlite3_user_data(sqlite3_context*);

/*
** CAPI3REF: Database Connection For Functions {F16250}
**
** The sqlite3_context_db_handle() interface returns a copy of
** the pointer to the [database connection] (the 1st parameter)
** of the [sqlite3_create_function()]
** and [sqlite3_create_function16()] routines that originally
** registered the application defined function.
**
** INVARIANTS:
**
** {F16253} The [sqlite3_context_db_handle(C)] interface returns a copy of the
**          D pointer from the [sqlite3_create_function(D,X,N,E,P,F,S,L)]

** invocations of the same function so that the original pattern string
** does not need to be recompiled on each invocation.
**
** The sqlite3_get_auxdata() interface returns a pointer to the meta-data
** associated by the sqlite3_set_auxdata() function with the Nth argument
** value to the application-defined function.
** If no meta-data has been ever been set for the Nth
** argument of the function, or if the corresponding function parameter
** has changed since the meta-data was set, then sqlite3_get_auxdata()
** returns a NULL pointer.
**
** The sqlite3_set_auxdata() interface saves the meta-data
** pointed to by its 3rd parameter as the meta-data for the N-th
** argument of the application-defined function.  Subsequent
** calls to sqlite3_get_auxdata() might return this data, if it has

** [sqlite3_bind_blob | sqlite3_bind_* documentation] for
** additional information.
**
** The sqlite3_result_blob() interface sets the result from
** an application defined function to be the BLOB whose content is pointed
** to by the second parameter and which is N bytes long where N is the
** third parameter. 
** The sqlite3_result_zeroblob() interfaces set the result of
** the application defined function to be a BLOB containing all zero
** bytes and N bytes in size, where N is the value of the 2nd parameter.
**
** The sqlite3_result_double() interface sets the result from
** an application defined function to be a floating point value specified
** by its 2nd argument.
**

** so that [sqlite3_value] specified in the parameter may change or
** be deallocated after sqlite3_result_value() returns without harm.
** A [protected sqlite3_value] object may always be used where an
** [unprotected sqlite3_value] object is required, so either
** kind of [sqlite3_value] object can be used with this interface.
**
** If these routines are called from within the different thread 
** than the one containing the application-defined function that received
** the [sqlite3_context] pointer, the results are undefined.
**
** INVARIANTS:
**
** {F16403} The default return value from any SQL function is NULL.
**
** {F16406} The [sqlite3_result_blob(C,V,N,D)] interface changes the

** that was passed as the third argument when the collation sequence was
** registered. {END} The application defined collation routine should
** return negative, zero or positive if
** the first string is less than, equal to, or greater than the second
** string. i.e. (STRING1 - STRING2).
**
** The sqlite3_create_collation_v2() works like sqlite3_create_collation()
** except that it takes an extra argument which is a destructor for
** the collation.  The destructor is called when the collation is
** destroyed and is passed a copy of the fourth parameter void* pointer
** of the sqlite3_create_collation_v2().
** Collations are destroyed when
** they are overridden by later calls to the collation creation functions
** or when the [sqlite3*] database handle is closed using [sqlite3_close()].
**

*/
int sqlite3_sleep(int);

/*
** CAPI3REF:  Name Of The Folder Holding Temporary Files {F10310}
**
** If this global variable is made to point to a string which is
** the name of a folder (a.k.a. directory), then all temporary files
** created by SQLite will be placed in that directory.  If this variable
** is NULL pointer, then SQLite does a search for an appropriate temporary
** file directory.
**
** It is not safe to modify this variable once a database connection
** has been opened.  It is intended that this variable be set once
** as part of process initialization and before any SQLite interface
** routines have been call and remain unchanged thereafter.
*/
SQLITE_EXTERN char *sqlite3_temp_directory;

/*
** CAPI3REF:  Test To See If The Database Is In Auto-Commit Mode {F12930}
**
** The sqlite3_get_autocommit() interface returns non-zero or
** zero if the given database connection is or is not in autocommit mode,
** respectively.   Autocommit mode is on
** by default.  Autocommit mode is disabled by a [BEGIN] statement.
** Autocommit mode is re-enabled by a [COMMIT] or [ROLLBACK].
**
** If certain kinds of errors occur on a statement within a multi-statement
** transactions (errors including [SQLITE_FULL], [SQLITE_IOERR], 
** [SQLITE_NOMEM], [SQLITE_BUSY], and [SQLITE_INTERRUPT]) then the
** transaction might be rolled back automatically.  The only way to
** find out if SQLite automatically rolled back the transaction after
** an error is to use this function.

int sqlite3_enable_shared_cache(int);

/*
** CAPI3REF:  Attempt To Free Heap Memory {F17340}
**
** The sqlite3_release_memory() interface attempts to
** free N bytes of heap memory by deallocating non-essential memory
** allocations held by the database library. {END}  Memory used
** to cache database pages to improve performance is an example of
** non-essential memory.  Sqlite3_release_memory() returns
** the number of bytes actually freed, which might be more or less
** than the amount requested.
**
** INVARIANTS:
**
** {F17341} The [sqlite3_release_memory(N)] interface attempts to
**          free N bytes of heap memory by deallocating non-essential
**          memory allocations held by the database library.
**
** {F16342} The [sqlite3_release_memory(N)] returns the number
**          of bytes actually freed, which might be more or less
**          than the amount requested.
*/
int sqlite3_release_memory(int);

** the memory is allocated anyway and the current operation proceeds.
**
** A negative or zero value for N means that there is no soft heap limit and
** [sqlite3_release_memory()] will only be called when memory is exhausted.
** The default value for the soft heap limit is zero.
**
** SQLite makes a best effort to honor the soft heap limit.  
** But if the soft heap limit cannot be honored, execution will
** continue without error or notification.  This is why the limit is 
** called a "soft" limit.  It is advisory only.
**
** Prior to SQLite version 3.5.0, this routine only constrained the memory
** allocated by a single thread - the same thread in which this routine
** runs.  Beginning with SQLite version 3.5.0, the soft heap limit is
** applied to all threads. The value specified for the soft heap limit

** The third and fourth parameters to this function are the table and column 
** name of the desired column, respectively. Neither of these parameters 
** may be NULL.
**
** Meta information is returned by writing to the memory locations passed as
** the 5th and subsequent parameters to this function. Any of these 
** arguments may be NULL, in which case the corresponding element of meta 
** information is omitted.
**
** <pre>
** Parameter     Output Type      Description
** -----------------------------------
**
**   5th         const char*      Data type
**   6th         const char*      Name of the default collation sequence 

/*
****** EXPERIMENTAL - subject to change without notice **************
**
** The interface to the virtual-table mechanism is currently considered
** to be experimental.  The interface might change in incompatible ways.
** If this is a problem for you, do not use the interface at this time.
**
** When the virtual-table mechanism stabilizes, we will declare the
** interface fixed, support it indefinitely, and remove this comment.
*/

/*
** Structures used by the virtual table interface
*/
typedef struct sqlite3_vtab sqlite3_vtab;

** must exist in order to be overloaded.
**
** This API makes sure a global version of a function with a particular
** name and number of parameters exists.  If no such function exists
** before this API is called, a new function is created.  The implementation
** of the new function always causes an exception to be thrown.  So
** the new function is not good for anything by itself.  Its only
** purpose is to be a placeholder function that can be overloaded
** by virtual tables.
**
** This API should be considered part of the virtual table interface,
** which is experimental and subject to change.
*/
int sqlite3_overload_function(sqlite3*, const char *zFuncName, int nArg);

**
** {F17819} The [sqlite3_blob_open()] interface returns [SQLITE_OK] on 
**          success and an appropriate [error code] on failure.
**
** {F17821} If an error occurs during evaluation of [sqlite3_blob_open(D,...)]
**          then subsequent calls to [sqlite3_errcode(D)],
**          [sqlite3_errmsg(D)], and [sqlite3_errmsg16(D)] will return
**          information appropriate for that error.
*/
int sqlite3_blob_open(
  sqlite3*,
  const char *zDb,
  const char *zTable,
  const char *zColumn,
  sqlite3_int64 iRow,

** {F17865} If the requested read could not be completed,
**          the [sqlite3_blob_read(P,Z,N,X)] interface returns an
**          appropriate [error code] or [extended error code].
**
** {F17868} If an error occurs during evaluation of [sqlite3_blob_read(P,...)]
**          then subsequent calls to [sqlite3_errcode(D)],
**          [sqlite3_errmsg(D)], and [sqlite3_errmsg16(D)] will return
**          information appropriate for that error, where D is the
**          database handle that was used to open blob handle P.
*/
int sqlite3_blob_read(sqlite3_blob *, void *Z, int N, int iOffset);

/*
** CAPI3REF:  Write Data Into A BLOB Incrementally {F17870}
**

** {F17885} If the requested write could not be completed,
**          the [sqlite3_blob_write(P,Z,N,X)] interface returns an
**          appropriate [error code] or [extended error code].
**
** {F17888} If an error occurs during evaluation of [sqlite3_blob_write(D,...)]
**          then subsequent calls to [sqlite3_errcode(D)],
**          [sqlite3_errmsg(D)], and [sqlite3_errmsg16(D)] will return
**          information appropriate for that error.
*/
int sqlite3_blob_write(sqlite3_blob *, const void *z, int n, int iOffset);

/*
** CAPI3REF:  Virtual File System Objects {F11200}
**
** A virtual filesystem (VFS) is an [sqlite3_vfs] object

** <li>   SQLITE_MUTEX_NOOP
** </ul>
**
** The SQLITE_MUTEX_NOOP implementation is a set of routines 
** that does no real locking and is appropriate for use in 
** a single-threaded application.  The SQLITE_MUTEX_OS2,
** SQLITE_MUTEX_PTHREAD, and SQLITE_MUTEX_W32 implementations
** are appropriate for use on OS/2, Unix, and Windows.
** 
** If SQLite is compiled with the SQLITE_MUTEX_APPDEF preprocessor
** macro defined (with "-DSQLITE_MUTEX_APPDEF=1"), then no mutex
** implementation is included with the library.  The
** mutex interface routines defined here become external
** references in the SQLite library for which implementations
** must be provided by the application.  This facility allows an

** use when they are deallocated. {U17022} Attempting to deallocate a static
** mutex results in undefined behavior. {F17023} SQLite never deallocates
** a static mutex. {END}
**
** The sqlite3_mutex_enter() and sqlite3_mutex_try() routines attempt
** to enter a mutex. {F17024} If another thread is already within the mutex,
** sqlite3_mutex_enter() will block and sqlite3_mutex_try() will return
** SQLITE_BUSY. {F17025}  The sqlite3_mutex_try() interface returns [SQLITE_OK]
** upon successful entry.  {F17026} Mutexes created using
** SQLITE_MUTEX_RECURSIVE can be entered multiple times by the same thread.
** {F17027} In such cases the,
** mutex must be exited an equal number of times before another thread
** can enter.  {U17028} If the same thread tries to enter any other
** kind of mutex more than once, the behavior is undefined.
** {F17029} SQLite will never exhibit

int sqlite3_file_control(sqlite3*, const char *zDbName, int op, void*);

/*
** CAPI3REF: Testing Interface {F11400}
**
** The sqlite3_test_control() interface is used to read out internal
** state of SQLite and to inject faults into SQLite for testing
** purposes.  The first parameter is an operation code that determines
** the number, meaning, and operation of all subsequent parameters.
**
** This interface is not for use by applications.  It exists solely
** for verifying the correct operation of the SQLite library.  Depending
** on how the SQLite library is compiled, this interface might not exist.
**
** The details of the operation codes, their meanings, the parameters
** they take, and what they do are all subject to change without notice.
** Unlike most of the SQLite API, this function is not guaranteed to
** operate consistently from one release to the next.
*/
int sqlite3_test_control(int op, ...);

/*
** CAPI3REF: Testing Interface Operation Codes {F11410}
**
** These constants are the valid operation code parameters used
** as the first argument to [sqlite3_test_control()].
**
** These parameters and their meanings are subject to change
** without notice.  These values are for testing purposes only.
** Applications should not use any of these parameters or the
** [sqlite3_test_control()] interface.
*/
#define SQLITE_TESTCTRL_FAULT_CONFIG             1
#define SQLITE_TESTCTRL_FAULT_FAILURES           2
#define SQLITE_TESTCTRL_FAULT_BENIGN_FAILURES    3