SQLite

  /* The column value supplied by SQLite must be in range. */
  assert( iCol>=0 && iCol<=p->nColumn+2 );

  switch( iCol-p->nColumn ){
    case 0:
      /* The special 'table-name' column */
      sqlite3_result_pointer(pCtx, pCsr, "fts3cursor");
      break;

    case 1:
      /* The docid column */
      sqlite3_result_int64(pCtx, pCsr->iPrevId);
      break;

static int fts3FunctionArg(
  sqlite3_context *pContext,      /* SQL function call context */
  const char *zFunc,              /* Function name */
  sqlite3_value *pVal,            /* argv[0] passed to function */
  Fts3Cursor **ppCsr              /* OUT: Store cursor handle here */
){
  int rc;
  *ppCsr = (Fts3Cursor*)sqlite3_value_pointer(pVal, "fts3cursor");
  if( (*ppCsr)!=0 ){
    rc = SQLITE_OK;
  }else{
    char *zErr = sqlite3_mprintf("illegal first argument to %s", zFunc);
    sqlite3_result_error(pContext, zErr, -1);
    sqlite3_free(zErr);
    rc = SQLITE_ERROR;

** Examples:
**
**      SELECT * FROM carray($ptr,5)
**
** The query above returns 5 integers contained in a C-language array
** at the address $ptr.  $ptr is a pointer to the array of integers.
** The pointer value must be assigned to $ptr using the
** sqlite3_bind_pointer() interface with a pointer type of "carray".
** For example:
**
**    static int aX[] = { 53, 9, 17, 2231, 4, 99 };
**    int i = sqlite3_bind_parameter_index(pStmt, "$ptr");
**    sqlite3_bind_value(pStmt, i, aX, "carray");
**
** There is an optional third parameter to determine the datatype of
** the C-language array.  Allowed values of the third parameter are
** 'int32', 'int64', 'double', 'char*'.  Example:
**
**      SELECT * FROM carray($ptr,10,'char*');
**
** The default value of the third parameter is 'int32'.
**
** HOW IT WORKS
**
** The carray "function" is really a virtual table with the
** following schema:
**
**     CREATE TABLE carray(

static int carrayFilter(
  sqlite3_vtab_cursor *pVtabCursor, 
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  carray_cursor *pCur = (carray_cursor *)pVtabCursor;
  if( idxNum ){
    pCur->pPtr = sqlite3_value_pointer(argv[0], "carray");
    pCur->iCnt = pCur->pPtr ? sqlite3_value_int64(argv[1]) : 0;
    if( idxNum<3 ){
      pCur->eType = CARRAY_INT32;
    }else{
      unsigned char i;
      const char *zType = (const char*)sqlite3_value_text(argv[2]);
      for(i=0; i<sizeof(azType)/sizeof(azType[0]); i++){

  i64 = sqlite3_value_int64(argv[0]);
  if( sizeof(i64)==sizeof(p) ){
    memcpy(&p, &i64, sizeof(p));
  }else{
    int i32 = i64 & 0xffffffff;
    memcpy(&p, &i32, sizeof(p));
  }
  sqlite3_result_pointer(context, p, "carray");
}
#endif /* SQLITE_TEST */

#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifdef _WIN32
__declspec(dllexport)

**
** This allows, for example, a counter to incremented and the original
** value retrieved, atomically, using a single statement:
**
**    UPDATE counterTab SET cnt=remember(cnt,$PTR)+1 WHERE id=$ID
**
** Prepare the above statement once.  Then to use it, bind the address
** of the output variable to $PTR using sqlite3_bind_pointer() with a
** pointer type of "carray" and bind the id of the counter to $ID and
** run the prepared statement.
**
** One can imagine doing similar things with floating-point values and
** strings, but this demonstration extension will stick to using just
** integers.
*/
#include "sqlite3ext.h"
SQLITE_EXTENSION_INIT1

  int argc,
  sqlite3_value **argv
){
  sqlite3_int64 v;
  sqlite3_int64 *ptr;
  assert( argc==2 );
  v = sqlite3_value_int64(argv[0]);
  ptr = sqlite3_value_pointer(argv[1], "carray");
  if( ptr ) *ptr = v;
  sqlite3_result_int64(pCtx, v);
}

#ifdef _WIN32
__declspec(dllexport)
#endif

** is filled with zeroes.  ^A zeroblob uses a fixed amount of memory
** (just an integer to hold its size) while it is being processed.
** Zeroblobs are intended to serve as placeholders for BLOBs whose
** content is later written using
** [sqlite3_blob_open | incremental BLOB I/O] routines.
** ^A negative value for the zeroblob results in a zero-length BLOB.
**
** ^The sqlite3_bind_pointer(S,I,P,T) routine causes the I-th parameter in
** [prepared statement] S to have an SQL value of NULL, but to also be
** associated with the pointer P of type T.
** ^The sqlite3_bind_pointer() routine can be used to pass
** host-language pointers into [application-defined SQL functions].
** ^A parameter that is initialized using [sqlite3_bind_pointer()] appears
** to be an ordinary SQL NULL value to everything other than
** [sqlite3_value_pointer()].
**
** ^If any of the sqlite3_bind_*() routines are called with a NULL pointer

int sqlite3_bind_int64(sqlite3_stmt*, int, sqlite3_int64);
int sqlite3_bind_null(sqlite3_stmt*, int);
int sqlite3_bind_text(sqlite3_stmt*,int,const char*,int,void(*)(void*));
int sqlite3_bind_text16(sqlite3_stmt*, int, const void*, int, void(*)(void*));
int sqlite3_bind_text64(sqlite3_stmt*, int, const char*, sqlite3_uint64,
                         void(*)(void*), unsigned char encoding);
int sqlite3_bind_value(sqlite3_stmt*, int, const sqlite3_value*);
int sqlite3_bind_pointer(sqlite3_stmt*, int, void*, const char*);
int sqlite3_bind_zeroblob(sqlite3_stmt*, int, int n);
int sqlite3_bind_zeroblob64(sqlite3_stmt*, int, sqlite3_uint64);

/*
** CAPI3REF: Number Of SQL Parameters
** METHOD: sqlite3_stmt
**

**
** ^The sqlite3_value_text16() interface extracts a UTF-16 string
** in the native byte-order of the host machine.  ^The
** sqlite3_value_text16be() and sqlite3_value_text16le() interfaces
** extract UTF-16 strings as big-endian and little-endian respectively.
**
** ^If [sqlite3_value] object V was initialized 
** using [sqlite3_bind_pointer(S,I,P,X)] or [sqlite3_result_pointer(C,P,X)]
** and if X and Y are strings that compare equal according to strcmp(X,Y),
** then sqlite3_value_pointer(V,Y) will return the pointer P.  ^Otherwise,
** sqlite3_value_pointer(V,Y) returns a NULL.
**
** ^(The sqlite3_value_type(V) interface returns the
** [SQLITE_INTEGER | datatype code] for the initial datatype of the
** [sqlite3_value] object V. The returned value is one of [SQLITE_INTEGER],
** [SQLITE_FLOAT], [SQLITE_TEXT], [SQLITE_BLOB], or [SQLITE_NULL].)^
** Other interfaces might change the datatype for an sqlite3_value object.
** For example, if the datatype is initially SQLITE_INTEGER and

** These routines must be called from the same thread as
** the SQL function that supplied the [sqlite3_value*] parameters.
*/
const void *sqlite3_value_blob(sqlite3_value*);
double sqlite3_value_double(sqlite3_value*);
int sqlite3_value_int(sqlite3_value*);
sqlite3_int64 sqlite3_value_int64(sqlite3_value*);
void *sqlite3_value_pointer(sqlite3_value*, const char*);
const unsigned char *sqlite3_value_text(sqlite3_value*);
const void *sqlite3_value_text16(sqlite3_value*);
const void *sqlite3_value_text16le(sqlite3_value*);
const void *sqlite3_value_text16be(sqlite3_value*);
int sqlite3_value_bytes(sqlite3_value*);
int sqlite3_value_bytes16(sqlite3_value*);
int sqlite3_value_type(sqlite3_value*);

** sqlite3_result_value() interface makes a copy of the [sqlite3_value]
** so that the [sqlite3_value] specified in the parameter may change or
** be deallocated after sqlite3_result_value() returns without harm.
** ^A [protected sqlite3_value] object may always be used where an
** [unprotected sqlite3_value] object is required, so either
** kind of [sqlite3_value] object can be used with this interface.
**
** ^The sqlite3_result_pointer(C,P,T) interface sets the result to an
** SQL NULL value, just like [sqlite3_result_null(C)], except that it
** also associates the host-language pointer P or type T with that 
** NULL value such that the pointer can be retrieved within an
** [application-defined SQL function] using [sqlite3_value_pointer()].
** This mechanism can be used to pass non-SQL values between
** application-defined functions.
**
** 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.

void sqlite3_result_text(sqlite3_context*, const char*, int, void(*)(void*));
void sqlite3_result_text64(sqlite3_context*, const char*,sqlite3_uint64,
                           void(*)(void*), unsigned char encoding);
void sqlite3_result_text16(sqlite3_context*, const void*, int, void(*)(void*));
void sqlite3_result_text16le(sqlite3_context*, const void*, int,void(*)(void*));
void sqlite3_result_text16be(sqlite3_context*, const void*, int,void(*)(void*));
void sqlite3_result_value(sqlite3_context*, sqlite3_value*);
void sqlite3_result_pointer(sqlite3_context*, void*, const char*);
void sqlite3_result_zeroblob(sqlite3_context*, int n);
int sqlite3_result_zeroblob64(sqlite3_context*, sqlite3_uint64 n);


/*
** CAPI3REF: Setting The Subtype Of An SQL Function
** METHOD: sqlite3_context

  /* Version 3.18.0 and later */
  void (*set_last_insert_rowid)(sqlite3*,sqlite3_int64);
  /* Version 3.20.0 and later */
  int (*prepare_v3)(sqlite3*,const char*,int,unsigned int,
                    sqlite3_stmt**,const char**);
  int (*prepare16_v3)(sqlite3*,const void*,int,unsigned int,
                      sqlite3_stmt**,const void**);
  int (*bind_pointer)(sqlite3_stmt*,int,void*,const char*);
  void (*result_pointer)(sqlite3_context*,void*,const char*);
  void *(*value_pointer)(sqlite3_value*,const char*);
};

/*
** This is the function signature used for all extension entry points.  It
** is also defined in the file "loadext.c".
*/
typedef int (*sqlite3_loadext_entry)(

int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*));
void sqlite3VdbeMemSetInt64(Mem*, i64);
#ifdef SQLITE_OMIT_FLOATING_POINT
# define sqlite3VdbeMemSetDouble sqlite3VdbeMemSetInt64
#else
  void sqlite3VdbeMemSetDouble(Mem*, double);
#endif
void sqlite3VdbeMemSetPointer(Mem*, void*, const char*);
void sqlite3VdbeMemInit(Mem*,sqlite3*,u16);
void sqlite3VdbeMemSetNull(Mem*);
void sqlite3VdbeMemSetZeroBlob(Mem*,int);
void sqlite3VdbeMemSetRowSet(Mem*);
int sqlite3VdbeMemMakeWriteable(Mem*);
int sqlite3VdbeMemStringify(Mem*, u8, u8);
i64 sqlite3VdbeIntValue(Mem*);

sqlite_int64 sqlite3_value_int64(sqlite3_value *pVal){
  return sqlite3VdbeIntValue((Mem*)pVal);
}
unsigned int sqlite3_value_subtype(sqlite3_value *pVal){
  Mem *pMem = (Mem*)pVal;
  return ((pMem->flags & MEM_Subtype) ? pMem->eSubtype : 0);
}
void *sqlite3_value_pointer(sqlite3_value *pVal, const char *zPType){
  Mem *p = (Mem*)pVal;
  if( p->flags==(MEM_Null|MEM_Subtype|MEM_Term|MEM_Static)
   && p->eSubtype=='p'
   && zPType!=0
   && strcmp(p->z, zPType)==0
  ){
    return p->u.pPtr;
  }else{
    return 0;
  }
}
const unsigned char *sqlite3_value_text(sqlite3_value *pVal){
  return (const unsigned char *)sqlite3ValueText(pVal, SQLITE_UTF8);

  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
  sqlite3VdbeMemSetInt64(pCtx->pOut, iVal);
}
void sqlite3_result_null(sqlite3_context *pCtx){
  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
  sqlite3VdbeMemSetNull(pCtx->pOut);
}
void sqlite3_result_pointer(sqlite3_context *pCtx, void *pPtr, const char *zPT){
  Mem *pOut = pCtx->pOut;
  assert( sqlite3_mutex_held(pOut->db->mutex) );
  sqlite3VdbeMemSetNull(pOut);
  sqlite3VdbeMemSetPointer(pOut, pPtr, zPT);
}
void sqlite3_result_subtype(sqlite3_context *pCtx, unsigned int eSubtype){
  Mem *pOut = pCtx->pOut;
  assert( sqlite3_mutex_held(pOut->db->mutex) );
  pOut->eSubtype = eSubtype & 0xff;
  pOut->flags |= MEM_Subtype;
}

  Vdbe *p = (Vdbe*)pStmt;
  rc = vdbeUnbind(p, i);
  if( rc==SQLITE_OK ){
    sqlite3_mutex_leave(p->db->mutex);
  }
  return rc;
}
int sqlite3_bind_pointer(sqlite3_stmt *pStmt, int i, void *pPtr,const char *zT){
  int rc;
  Vdbe *p = (Vdbe*)pStmt;
  rc = vdbeUnbind(p, i);
  if( rc==SQLITE_OK ){
    sqlite3VdbeMemSetPointer(&p->aVar[i-1], pPtr, zT);
    sqlite3_mutex_leave(p->db->mutex);
  }
  return rc;
}
int sqlite3_bind_text( 
  sqlite3_stmt *pStmt, 
  int i, 

  }
}

/*
** Set the value stored in *pMem should already be a NULL.
** Also store a pointer to go with it.
*/
void sqlite3VdbeMemSetPointer(Mem *pMem, void *pPtr, const char *zPType){
  assert( pMem->flags==MEM_Null );
  if( zPType ){
    pMem->flags = MEM_Null|MEM_Subtype|MEM_Term|MEM_Static;
    pMem->u.pPtr = pPtr;
    pMem->eSubtype = 'p';
    pMem->z = (char*)zPType;
  }
}

#ifndef SQLITE_OMIT_FLOATING_POINT
/*
** Delete any previous value and set the value stored in *pMem to val,
** manifest type REAL.
*/