PHP Manual: set_include

function set_include_path(string $include_path): string|false

Sets the include_path configuration option for the duration of the script.

Returns the old include_path on success or false on failure.

Example #1 set_include_path() example

<?php
set_include_path('/usr/lib/pear');

// Or using ini_set()
ini_set('include_path', '/usr/lib/pear');
?>

Example #2 Adding to the include path

Making use of the PATH_SEPARATOR constant, it is possible to extend the include path regardless of the operating system.

In this example we add /usr/lib/pear to the end of the existing include_path.

<?php
$path = '/usr/lib/pear';
set_include_path(get_include_path() . PATH_SEPARATOR . $path);
?>

set_include_path