}

#ifndef SQLITE_OMIT_WAL
/*
** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
** Return non-zero, indicating to the caller that a checkpoint should be run,
** if the number of frames in the log file is greater than 

** sqlite3.nAutoCheckpoint (the value configured by wal_autocheckpoint()).
*/ 
static int defaultWalHook(void *p, sqlite3 *db, const char *z, int nFrame){
  UNUSED_PARAMETER(p);





  UNUSED_PARAMETER(z);
  return ( nFrame>=db->nAutoCheckpoint );
}


/*
** Configure an sqlite3_wal_hook() callback to automatically checkpoint
** a database after committing a transaction if there are nFrame or
** more frames in the log file. Passing zero or a negative value as the
** nFrame parameter disables automatic checkpoints entirely.
**
** The callback registered by this function replaces any existing callback
** registered using sqlite3_wal_hook(). Likewise, registering a callback
** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
** configured by this function.
*/
int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){

  sqlite3_mutex_enter(db->mutex);
  if( nFrame>0 ){
    sqlite3_wal_hook(db, defaultWalHook, 0);
    db->nAutoCheckpoint = nFrame;
  }else{
    sqlite3_wal_hook(db, 0, 0);
  }
  sqlite3_mutex_leave(db->mutex);

  return SQLITE_OK;
}

/*
** Register a callback to be invoked each time a transaction is written
** into the write-ahead-log by this database connection.
*/
void *sqlite3_wal_hook(
  sqlite3 *db,                    /* Attach the hook to this db handle */
  int(*xCallback)(void *, sqlite3*, const char*, int),
  void *pArg                      /* First argument passed to xCallback() */
){

  void *pRet;
  sqlite3_mutex_enter(db->mutex);
  pRet = db->pWalArg;
  db->xWalCallback = xCallback;
  db->pWalArg = pArg;
  db->nAutoCheckpoint = 0;
  sqlite3_mutex_leave(db->mutex);
  return pRet;



}


/*
** Checkpoint database zDb. If zDb is NULL, the main database is checkpointed.
*/
int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){



  int rc;                         /* Return code */
  int iDb = 0;                    /* sqlite3.aDb[] index of db to checkpoint */

  sqlite3_mutex_enter(db->mutex);
  if( zDb ){
    iDb = sqlite3FindDbName(db, zDb);
  }
................................................................................
  if( iDb<0 ){
    rc = SQLITE_ERROR;
    sqlite3Error(db, SQLITE_ERROR, "unknown database: %s", zDb);
  }else{
    rc = sqlite3Checkpoint(db, iDb);
    sqlite3Error(db, rc, 0);
  }

  sqlite3_mutex_leave(db->mutex);

  return sqlite3ApiExit(db, rc);

}


/*
** Run a checkpoint on database iDb. This is a no-op if database iDb is
** not currently open in WAL mode.
**
** If a transaction is open at either the database handle (db) or b-tree
** level, this function returns SQLITE_LOCKED and a checkpoint is not
** attempted. If an error occurs while running the checkpoint, an SQLite
................................................................................
    sqlite3BtreeEnter(pBt);
    rc = sqlite3PagerCheckpoint(sqlite3BtreePager(pBt));
    sqlite3BtreeLeave(pBt);
  }

  return rc;
}
#else /* ifndef SQLITE_OMIT_WAL */
/*
** If SQLITE_OMIT_WAL is defined, the following API functions are no-ops:
**
**   sqlite3_wal_hook()
**   sqlite3_wal_checkpoint()
**   sqlite3_wal_autocheckpoint()
*/
void *sqlite3_wal_hook(
  sqlite3 *x,
  int(*xCallback)(void *, sqlite3*, const char*, int),
  void *pArg
){
  return 0;
}
int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){ return SQLITE_OK; }
int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){ return SQLITE_OK; }
#endif

/*
** This function returns true if main-memory should be used instead of
** a temporary file for transient pager files and statement journals.
** The value returned depends on the value of db->temp_store (runtime
** parameter) and the compile time value of SQLITE_TEMP_STORE. The
** following table describes the relationship between these two values

}

#ifndef SQLITE_OMIT_WAL
/*
** The sqlite3_wal_hook() callback registered by sqlite3_wal_autocheckpoint().
** Return non-zero, indicating to the caller that a checkpoint should be run,
** if the number of frames in the log file is greater than 
** sqlite3.pWalArg cast to an integer (the value configured by
** wal_autocheckpoint()).
*/ 

int sqlite3WalDefaultHook(
  void *p,               /* Argument */
  sqlite3 *db,           /* Connection */
  const char *zNotUsed,  /* Database */
  int nFrame             /* Size of WAL */
){
  UNUSED_PARAMETER(zNotUsed);
  return ( nFrame>=SQLITE_PTR_TO_INT(p));
}
#endif /* SQLITE_OMIT_WAL */

/*
** Configure an sqlite3_wal_hook() callback to automatically checkpoint
** a database after committing a transaction if there are nFrame or
** more frames in the log file. Passing zero or a negative value as the
** nFrame parameter disables automatic checkpoints entirely.
**
** The callback registered by this function replaces any existing callback
** registered using sqlite3_wal_hook(). Likewise, registering a callback
** using sqlite3_wal_hook() disables the automatic checkpoint mechanism
** configured by this function.
*/
int sqlite3_wal_autocheckpoint(sqlite3 *db, int nFrame){
#ifndef SQLITE_OMIT_WAL
  sqlite3_mutex_enter(db->mutex);
  if( nFrame>0 ){
    sqlite3_wal_hook(db, sqlite3WalDefaultHook, SQLITE_INT_TO_PTR(nFrame));

  }else{
    sqlite3_wal_hook(db, 0, 0);
  }
  sqlite3_mutex_leave(db->mutex);
#endif
  return SQLITE_OK;
}

/*
** Register a callback to be invoked each time a transaction is written
** into the write-ahead-log by this database connection.
*/
void *sqlite3_wal_hook(
  sqlite3 *db,                    /* Attach the hook to this db handle */
  int(*xCallback)(void *, sqlite3*, const char*, int),
  void *pArg                      /* First argument passed to xCallback() */
){
#ifndef SQLITE_OMIT_WAL
  void *pRet;
  sqlite3_mutex_enter(db->mutex);
  pRet = db->pWalArg;
  db->xWalCallback = xCallback;
  db->pWalArg = pArg;

  sqlite3_mutex_leave(db->mutex);
  return pRet;
#else
  return 0;
#endif
}


/*
** Checkpoint database zDb. If zDb is NULL, the main database is checkpointed.
*/
int sqlite3_wal_checkpoint(sqlite3 *db, const char *zDb){
#ifdef SQLITE_OMIT_WAL
  return SQLITE_OK;
#else
  int rc;                         /* Return code */
  int iDb = 0;                    /* sqlite3.aDb[] index of db to checkpoint */

  sqlite3_mutex_enter(db->mutex);
  if( zDb ){
    iDb = sqlite3FindDbName(db, zDb);
  }
................................................................................
  if( iDb<0 ){
    rc = SQLITE_ERROR;
    sqlite3Error(db, SQLITE_ERROR, "unknown database: %s", zDb);
  }else{
    rc = sqlite3Checkpoint(db, iDb);
    sqlite3Error(db, rc, 0);
  }
  rc = sqlite3ApiExit(db, rc);
  sqlite3_mutex_leave(db->mutex);

  return rc;
#endif
}

#ifndef SQLITE_OMIT_WAL
/*
** Run a checkpoint on database iDb. This is a no-op if database iDb is
** not currently open in WAL mode.
**
** If a transaction is open at either the database handle (db) or b-tree
** level, this function returns SQLITE_LOCKED and a checkpoint is not
** attempted. If an error occurs while running the checkpoint, an SQLite
................................................................................
    sqlite3BtreeEnter(pBt);
    rc = sqlite3PagerCheckpoint(sqlite3BtreePager(pBt));
    sqlite3BtreeLeave(pBt);
  }

  return rc;
}
#endif /* SQLITE_OMIT_WAL */


















/*
** This function returns true if main-memory should be used instead of
** a temporary file for transient pager files and statement journals.
** The value returned depends on the value of db->temp_store (runtime
** parameter) and the compile time value of SQLITE_TEMP_STORE. The
** following table describes the relationship between these two values

  ** of N.
  */
  if( sqlite3StrICmp(zLeft, "wal_autocheckpoint")==0 ){
    if( zRight ){
      int nAuto = atoi(zRight);
      sqlite3_wal_autocheckpoint(db, nAuto);
    }
    returnSingleInt(pParse, "wal_autocheckpoint", db->nAutoCheckpoint);


  }else
#endif

#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
  /*
  ** Report the current state of file logs for all databases
  */

  ** of N.
  */
  if( sqlite3StrICmp(zLeft, "wal_autocheckpoint")==0 ){
    if( zRight ){
      int nAuto = atoi(zRight);
      sqlite3_wal_autocheckpoint(db, nAuto);
    }
    returnSingleInt(pParse, "wal_autocheckpoint", 
       db->xWalCallback==sqlite3WalDefaultHook ? 
           SQLITE_PTR_TO_INT(db->pWalArg) : 0);
  }else
#endif

#if defined(SQLITE_DEBUG) || defined(SQLITE_TEST)
  /*
  ** Report the current state of file logs for all databases
  */

  void *pCommitArg;                 /* Argument to xCommitCallback() */   
  int (*xCommitCallback)(void*);    /* Invoked at every commit. */
  void *pRollbackArg;               /* Argument to xRollbackCallback() */   
  void (*xRollbackCallback)(void*); /* Invoked at every commit. */
  void *pUpdateArg;
  void (*xUpdateCallback)(void*,int, const char*,const char*,sqlite_int64);
#ifndef SQLITE_OMIT_WAL
  int nAutoCheckpoint;          /* Value configured by wal_autocheckpoint() */
  int (*xWalCallback)(void *, sqlite3 *, const char *, int);
  void *pWalArg;
#endif
  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*);
  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*);
  void *pCollNeededArg;
  sqlite3_value *pErr;          /* Most recent error message */
................................................................................
int sqlite3Reprepare(Vdbe*);
void sqlite3ExprListCheckLength(Parse*, ExprList*, const char*);
CollSeq *sqlite3BinaryCompareCollSeq(Parse *, Expr *, Expr *);
int sqlite3TempInMemory(const sqlite3*);
VTable *sqlite3GetVTable(sqlite3*, Table*);
const char *sqlite3JournalModename(int);
int sqlite3Checkpoint(sqlite3*, int);


/* Declarations for functions in fkey.c. All of these are replaced by
** no-op macros if OMIT_FOREIGN_KEY is defined. In this case no foreign
** key functionality is available. If OMIT_TRIGGER is defined but
** OMIT_FOREIGN_KEY is not, only some of the functions are no-oped. In
** this case foreign keys are parsed, but no other functionality is 
** provided (enforcement of FK constraints requires the triggers sub-system).

  void *pCommitArg;                 /* Argument to xCommitCallback() */   
  int (*xCommitCallback)(void*);    /* Invoked at every commit. */
  void *pRollbackArg;               /* Argument to xRollbackCallback() */   
  void (*xRollbackCallback)(void*); /* Invoked at every commit. */
  void *pUpdateArg;
  void (*xUpdateCallback)(void*,int, const char*,const char*,sqlite_int64);
#ifndef SQLITE_OMIT_WAL

  int (*xWalCallback)(void *, sqlite3 *, const char *, int);
  void *pWalArg;
#endif
  void(*xCollNeeded)(void*,sqlite3*,int eTextRep,const char*);
  void(*xCollNeeded16)(void*,sqlite3*,int eTextRep,const void*);
  void *pCollNeededArg;
  sqlite3_value *pErr;          /* Most recent error message */
................................................................................
int sqlite3Reprepare(Vdbe*);
void sqlite3ExprListCheckLength(Parse*, ExprList*, const char*);
CollSeq *sqlite3BinaryCompareCollSeq(Parse *, Expr *, Expr *);
int sqlite3TempInMemory(const sqlite3*);
VTable *sqlite3GetVTable(sqlite3*, Table*);
const char *sqlite3JournalModename(int);
int sqlite3Checkpoint(sqlite3*, int);
int sqlite3WalDefaultHook(void*,sqlite3*,const char*,int);

/* Declarations for functions in fkey.c. All of these are replaced by
** no-op macros if OMIT_FOREIGN_KEY is defined. In this case no foreign
** key functionality is available. If OMIT_TRIGGER is defined but
** OMIT_FOREIGN_KEY is not, only some of the functions are no-oped. In
** this case foreign keys are parsed, but no other functionality is 
** provided (enforcement of FK constraints requires the triggers sub-system).