7.5 compatibility_alias
This is a feature of the Objective-C compiler rather than of the runtime, anyway since it is documented nowhere and its existence was forgotten, we are documenting it here.
The keyword @compatibility_alias
allows you to define a class name as equivalent to another class name. For example:
@compatibility_alias WOApplication GSWApplication;
tells the compiler that each time it encounters WOApplication
as a class name, it should replace it with GSWApplication
(that is, WOApplication
is just an alias for GSWApplication
).
There are some constraints on how this can be used—
-
WOApplication
(the alias) must not be an existing class; -
GSWApplication
(the real class) must be an existing class.