61   int errorcode = pthread_rwlock_init(rwlock, nullptr);  in RWMutexImpl()  local
62   (void)errorcode;  in RWMutexImpl()
63   assert(errorcode == 0);  in RWMutexImpl()
84   int errorcode = pthread_rwlock_rdlock(rwlock);  in reader_acquire()  local
85   return errorcode == 0;  in reader_acquire()
94   int errorcode = pthread_rwlock_unlock(rwlock);  in reader_release()  local
95   return errorcode == 0;  in reader_release()
104   int errorcode = pthread_rwlock_wrlock(rwlock);  in writer_acquire()  local
105   return errorcode == 0;  in writer_acquire()
114   int errorcode = pthread_rwlock_unlock(rwlock);  in writer_release()  local
115   return errorcode == 0;  in writer_release()