source: asp3_tinet_ecnl_arm/trunk/musl-1.1.18/src/thread/pthread_rwlock_tryrdlock.c@ 352

#include "pthread_impl.h"

int pthread_rwlock_tryrdlock(pthread_rwlock_t *rw)
{
        int val, cnt;
        do {
                val = rw->_rw_lock;
                cnt = val & 0x7fffffff;
                if (cnt == 0x7fffffff) return EBUSY;
                if (cnt == 0x7ffffffe) return EAGAIN;
        } while (a_cas(&rw->_rw_lock, val, val+1) != val);
        return 0;
}