How does the PHP network function fsockopen implement Socket link_PHP tutorial

Syntax: int fsockopen(string hostname, int port, int [errno], string [errstr], int [timeout]);

Return value: integer

Function type: Network system content description: Currently, the PHP network function fsockopen provides two Socket data flow interfaces, namely AF_INET for Internet and AF_UNIX for Unix. When used in the context of the Internet, the parameters hostname and port represent the URL and port number respectively. In UNIX, IPC can be done. The hostname parameter indicates the path to the socket and the port is configured as 0. The omitted timeout option indicates how long it will take before the connection is interrupted. After using this function, the file pointer will be returned for use by file functions, including fgets(), fgetss(), fputs(), fclose() and feof(). The parameters errno and errstr are also omitted and are mainly used for error handling. Using this function will use blocking mode processing, which can be converted to non-blocking mode with set_socket_blocking().

Usage example of PHP network function fsockopen. This example is used to simulate an HTTP connection.

<ol class="dp-xml">
<li class="alt"><span><span class="tag"><?</span><span class="tag-name">php</span><span> </span></span></li><li><span>$</span><span class="attribute">fp</span><span> = </span><span class="attribute-value">fsockopen</span><span>("php.wilson.gs", 80, &$errno, &$errstr, 10);  </span></li><li class="alt"><span>if(!$fp) {  </span></li><li><span>echo "$errstr ($errno)</span><span class="tag"><</span><span class="tag-name">br</span><span class="tag">></span><span>n";  </span></span></li>
<li class="alt"><span>} else {  </span></li>
<li><span>fputs($fp,"GET / HTTP/1.0nHost： php.wilson.gsnn");  </span></li>
<li class="alt"><span>while(!feof($fp)) {  </span></li>
<li><span>echo fgets($fp,128);  </span></li>
<li class="alt"><span>}  </span></li>
<li><span>fclose($fp);  </span></li>
<li class="alt"><span>}  </span></li>
<li>
<span></span><span class="tag">?></span><span>  </span>
</li>
</ol>

Through the above example of using the PHP network function fsockopen, have readers basically mastered the usage of this function?