Question

In this question I was looking for a way to ensure that a variable is of a certain type using a define. But sometimes I have this situation:

- (void) theSituation:(Thinger*)thinger {
    ASSERT_IS_KIND_OF(thinger, Thinger);
    // etc. etc.

Then I started thinking that, for debugging purposes ONLY, it might be nice to be able to call something like:

- (void) theSituation:(Thinger*)thinger {
    ASSERT_INPUT_PARAMS_ARE_OF_CORRECT_TYPES();
    // etc. etc.

The question is: could you check that parameters of a method are of the right type (using isKindOf) via #define, and how would you do this (in general terms)?

Answer 1

When you get the arguments of a method (using method_copyArgumentType as mentioned in the other answer), the “type” it returns is either a C type (like int, float, etc) or just Object (returned as a “@”). Sadly it’s not possible to get the objective-C type that a method is expecting — that information is lost when you compile.

Answer to a similar problem found here.