一只菜鸟的电子记事本

动态加载 PHP 扩展

<?php
if (!extension_loaded('gd')) {    // 如果没有加载 gd 库
if (!dl('gd.so')) {    // 那么就动态加载
exit;
}
}
?>

关于使用 dl() 要注意的（以下内容摘自 php 手册）：

注意: dl() is not supported
in multithreaded Web servers. Use the extensions statement in your
php.ini when operating under such an environment. However, the
CGI and CLI build are not affected !

注意: As of PHP 5, the dl() function is deprecated in every SAPI
except CLI. Use Extension
Loading Directives method instead.

注意: Since PHP 6 this function is disabled in all SAPIs, except CLI,
CGI and embed.

注意: dl() is case sensitive on Unix platforms.

注意: 本函数在安全模式下被禁用。