If you are trying to find a file on your include path, there is a better way: http://php.net/manual/en/function.stream-resolve-include-path.php
(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
get_include_path — 获取当前的 include_path 配置选项
此函数没有参数。
返回字符串的路径， 或者在失败时返回 false。
示例 #1 get_include_path() 示例
<?php
echo get_include_path();
// 或使用 ini_get()
echo ini_get('include_path');
?>
If you are trying to find a file on your include path, there is a better way: http://php.net/manual/en/function.stream-resolve-include-path.php