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 — Gets the current include_path configuration option
Gets the current include_path configuration option value.
This function has no parameters.
Returns the path, as a string, or false on failure.
Example #1 get_include_path() example
<?php
echo get_include_path();
// Or using 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