xref: /aosp_15_r20/external/musl/src/thread/pthread_rwlock_tryrdlock.c (revision c9945492fdd68bbe62686c5b452b4dc1be3f8453)
1*c9945492SAndroid Build Coastguard Worker #include "pthread_impl.h"
2*c9945492SAndroid Build Coastguard Worker 
__pthread_rwlock_tryrdlock(pthread_rwlock_t * rw)3*c9945492SAndroid Build Coastguard Worker int __pthread_rwlock_tryrdlock(pthread_rwlock_t *rw)
4*c9945492SAndroid Build Coastguard Worker {
5*c9945492SAndroid Build Coastguard Worker 	int val, cnt;
6*c9945492SAndroid Build Coastguard Worker 	do {
7*c9945492SAndroid Build Coastguard Worker 		val = rw->_rw_lock;
8*c9945492SAndroid Build Coastguard Worker 		cnt = val & 0x7fffffff;
9*c9945492SAndroid Build Coastguard Worker 		if (cnt == 0x7fffffff) return EBUSY;
10*c9945492SAndroid Build Coastguard Worker 		if (cnt == 0x7ffffffe) return EAGAIN;
11*c9945492SAndroid Build Coastguard Worker 	} while (a_cas(&rw->_rw_lock, val, val+1) != val);
12*c9945492SAndroid Build Coastguard Worker 	return 0;
13*c9945492SAndroid Build Coastguard Worker }
14*c9945492SAndroid Build Coastguard Worker 
15*c9945492SAndroid Build Coastguard Worker weak_alias(__pthread_rwlock_tryrdlock, pthread_rwlock_tryrdlock);
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