(PHP 4 >= 4.3.0, PHP 5, PHP 7, PHP 8)
set_include_path — Sets the include_path configuration option
$include_path): string|falseSets 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);
?>