int i;   /* global variable */
pthread_mutex_t loopLock = PTHREAD_MUTEX_INITIALIZER;
  .
  .
void fn( void )
{
  pthread_mutex_lock( &loopLock );
  for( i = 0; i != 4; ++i ) {
    printf( ``%d '', i );
  }
  printf( ``\n'' );
  pthread_mutex_unlock( &loopLock );
}
  .
  .