set_include_path Sets the include_path configuration option stringset_include_path stringnew_include_path Sets the include_path configuration option for the duration of the script. Returns the old include_path on success or &false; on failure. ]]> 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. ]]> See also ini_set, get_include_path, restore_include_path, and include.