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