53   int errorcode = pthread_rwlock_init(rwlock, nullptr);  in RWMutexImpl()  local
54   (void)errorcode;  in RWMutexImpl()
55   assert(errorcode == 0);  in RWMutexImpl()
76   int errorcode = pthread_rwlock_rdlock(rwlock);  in lock_shared()  local
77   return errorcode == 0;  in lock_shared()
86   int errorcode = pthread_rwlock_unlock(rwlock);  in unlock_shared()  local
87   return errorcode == 0;  in unlock_shared()
96   int errorcode = pthread_rwlock_wrlock(rwlock);  in lock()  local
97   return errorcode == 0;  in lock()
106   int errorcode = pthread_rwlock_unlock(rwlock);  in unlock()  local
107   return errorcode == 0;  in unlock()