Predefined IUP action, generated every time an action has no associated function.
int function(Ihandle *self); [in C] [There is no Lua equivalent]
self: identifier of the element that activated the function.
Often a programmer defines an action with a name and, when associating it to a function, he/she mistypes the action name, or vice-versa. This kind of mistake is very common, and IUP is not able to automatically detect it. The predefined IUP_DEFAULT_ACTION action, combined with function IupGetActionName, can help the programmer detect this problem. All you have to do is define a default action and verify which is the name of the action that activated it.