text: /*
  ** 2004 January 13
  **
  ** 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 file implements a simple standalone program used to test whether
  ** or not the SQLite library is threadsafe.
  **
  ** This file is NOT part of the standard SQLite library.  It is used for
  ** testing only.
  */
  #include <stdio.h>
  #include <unistd.h>
  #include <pthread.h>
  #include <string.h>
  #include <stdlib.h>
  #include "sqlite.h"
  
  /*
  ** Name of the database
  */
  #define DB_FILE "test.db"
  
  /* 
  ** When this variable becomes non-zero, all threads stop
  ** what they are doing.
  */
  volatile int all_stop = 0;
  
  /* 
  ** Callback from the integrity check.  If the result is anything other
  ** than "ok" it means the integrity check has failed.  Set the "all_stop"
  ** global variable to stop all other activity.  Print the error message
  ** or print OK if the string "ok" is seen.
  */
  int check_callback(void *pid, int argc, char **argv, char **notUsed2){
    int id = (int)pid;
    if( strcmp(argv[0],"ok") ){
      all_stop = 1;
      fprintf(stderr,"%d: %s\n", id, argv[0]);
    }else{
      /* fprintf(stderr,"%d: OK\n", id); */
    }
    return 0;
  }
  
  /*
  ** Do an integrity check on the database.  If the first integrity check
  ** fails, try it a second time.
  */
  int integrity_check(sqlite *db, int id){
    int rc;
    if( all_stop ) return 0;
    /* fprintf(stderr,"%d: CHECK\n", id); */
    rc = sqlite3_exec(db, "pragma integrity_check", check_callback, 0, 0);
    if( rc!=SQLITE_OK && rc!=SQLITE_BUSY ){
      fprintf(stderr,"%d, Integrity check returns %d\n", id, rc);
    }
    if( all_stop ){
      sqlite3_exec(db, "pragma integrity_check", check_callback, 0, 0);
    }
    return 0;
  }
  
  /*
  ** This is the worker thread
  */
  void *worker(void *workerArg){
    sqlite *db;
    int id = (int)workerArg;
    int rc;
    int cnt = 0;
    fprintf(stderr, "Starting worker %d\n", id);
    while( !all_stop && cnt++<10000 ){
      if( cnt%100==0 ) printf("%d: %d\n", id, cnt);
      while( (sqlite3_open(DB_FILE, &db))!=SQLITE_OK ) sched_yield();
      sqlite3_exec(db, "PRAGMA synchronous=OFF", 0, 0, 0);
      /* integrity_check(db, id); */
      if( all_stop ){ sqlite3_close(db); break; }
      /* fprintf(stderr, "%d: BEGIN\n", id); */
      rc = sqlite3_exec(db, "INSERT INTO t1 VALUES('bogus data')", 0, 0, 0);
      /* fprintf(stderr, "%d: END rc=%d\n", id, rc); */
      sqlite3_close(db);
    }
    fprintf(stderr, "Worker %d finished\n", id);
    return 0;
  }
  
  /*
  ** Initialize the database and start the threads
  */
  int main(int argc, char **argv){
    sqlite *db;
    int i, rc;
    pthread_t aThread[5];
  
    if( strcmp(DB_FILE,":memory:") ){
      char *zJournal = sqlite3_mprintf("%s-journal", DB_FILE);
      unlink(DB_FILE);
      unlink(zJournal);
      sqlite3_free(zJournal);
    }  
    sqlite3_open(DB_FILE, &db);
    if( db==0 ){
      fprintf(stderr,"unable to initialize database\n");
      exit(1);
    }
    rc = sqlite3_exec(db, "CREATE TABLE t1(x);", 0,0,0);
    if( rc ){
      fprintf(stderr,"cannot create table t1: %d\n", rc);
      exit(1);
    }
    sqlite3_close(db);
    for(i=0; i<sizeof(aThread)/sizeof(aThread[0]); i++){
      pthread_create(&aThread[i], 0, worker, (void*)i);
    }
    for(i=0; i<sizeof(aThread)/sizeof(aThread[i]); i++){
      pthread_join(aThread[i], 0);
    }
    if( !all_stop ){
      printf("Everything seems ok.\n");
      return 0;
    }else{
      printf("We hit an error.\n");
      return 1;
    }
  }
  