(PHP 5)
streamWrapper::stream_lock — Advisory file locking
This method is called in response to flock(), when file_put_contents() (when flags contains LOCK_EX), stream_set_blocking() and when closing the stream (LOCK_UN).
operation is one of the following:
성공할 경우 TRUE를, 실패할 경우 FALSE를 반환합니다.
Emits E_WARNING if call to this method fails (i.e. not implemented).