interface_exists Checks if the interface has been defined boolinterface_exists stringinterface_name boolautoload This function returns &true; if the interface given by interface_name has been defined, &false; otherwise. ]]> interface_exists will attempt to call &link.autoload; by default, if you don't want interface_exists to call &link.autoload;, you can set the parameter autoload to &false;. See also class_exists.