void av_register_hwaccel(AVHWAccel *hwaccel)
{
    AVHWAccel **p = last_hwaccel;
    hwaccel->next = NULL;
    while(*p || avpriv_atomic_ptr_cas((void * volatile *)p, NULL, hwaccel))
        p = &(*p)->next;
    last_hwaccel = &hwaccel->next;
}
Unknown