int pthread_rwlock_trywrlock(pthread_rwlock_t *rw)
{
- if (a_xchg(&rw->__wrlock, 1))
- return EAGAIN;
- if (rw->__readers) {
- a_store(&rw->__wrlock, 0);
- return EAGAIN;
- }
- rw->__owner = pthread_self()->tid;
+ if (a_cas(&rw->_rw_lock, 0, 0x7fffffff)) return EBUSY;
return 0;
}