Sets the timeout value on stream, expressed in the sum of seconds and microseconds. 如果成功则返回 TRUE,失败则返回 FALSE。
When the stream times out, the 'timed_out' key of the array returned by stream_get_meta_data() is set to TRUE, although no error/warning is generated.
注: As of PHP 4.3, this function can (potentially) work on any kind of stream. In PHP 4.3, socket based streams are still the only kind supported in the PHP core, although streams from other extensions may support this function.
This function was previously called as set_socket_timeout() and later socket_set_timeout() but this usage is deprecated.
See also fsockopen() and fopen().