(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
stream_set_timeout — Set timeout period on a stream
$stream, int $seconds, int $microseconds = 0): bool
   Sets the timeout value on stream,
   expressed in the sum of seconds and
   microseconds. 
  
   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.
  
streamThe target stream.
secondsThe seconds part of the timeout to be set.
microsecondsThe microseconds part of the timeout to be set.
   成功时返回 true, 或者在失败时返回 false。
  
示例 #1 stream_set_timeout() example
<?php
$fp = fsockopen("www.example.com", 80);
if (!$fp) {
    echo "Unable to open\n";
} else {
    fwrite($fp, "GET / HTTP/1.0\r\n\r\n");
    stream_set_timeout($fp, 2);
    $res = fread($fp, 2000);
    $info = stream_get_meta_data($fp);
    fclose($fp);
    if ($info['timed_out']) {
        echo 'Connection timed out!';
    } else {
        echo $res;
    }
}
?>
注意:
This function doesn't work with advanced operations like stream_socket_recvfrom(), use stream_select() with timeout parameter instead.
This function was previously called as set_socket_timeout() and later socket_set_timeout() but this usage is deprecated.