Python获取GIL锁的过程

int  PyThread_acquire_lock(PyThread_type_lock lock, int waitflag)
{
    int success;
    pthread_lock *thelock = (pthread_lock *)lock;
    int status, error = 0;
    status = pthread_mutex_lock( &thelock->mut );
    success = thelock->locked == 0;
    if ( !success && waitflag ) {
        while ( thelock->locked ) {
            status = pthread_cond_wait(&thelock->lock_released,
                                       &thelock->mut);
        }
        success = 1;
    }
    if (success) thelock->locked = 1;
    status = pthread_mutex_unlock( &thelock->mut );
    if (error) success = 0;
    return success;
}