GC_API void GC_CALL GC_set_finalizer_notifier(GC_finalizer_notifier_proc fn)
{
    /* fn may be 0 (means no finalizer notifier). */
    DCL_LOCK_STATE;
    LOCK();
    GC_finalizer_notifier = fn;
    UNLOCK();
}
GC_API void GC_CALL GC_set_finalizer_notifier(GC_finalizer_notifier_proc fn)
{
     
    DCL_LOCK_STATE;
    LOCK();
    GC_finalizer_notifier = fn;
    UNLOCK();
}