Thanks for trying it out - my post was assembled by copying bits out of the (rather gnarlier) code that I actually used, so I'm glad it mostly survived the process ;)

Interesting point about the type checking; my thinking was that the compiler could check they matched, and that this would suffice - and sure enough it worked absolutely fine in practice. But now that I'm made to think about it again, I think it's probably still not quite good enough to be perfect, because you could do this:

    void f(ARRAY_PARAMS(const char *,*xs)) {
        ARRAY_ADD(*xs,"fred");
    }

    ...
    ARRAY(char *,xs);
    ARRAY_INIT(xs);
    f(&xs);

And now you've got a char * that points to a const string. Erm... that's not good!

EDIT: maybe I see what you're getting at with ARRAY_ARG now. The intention is that you use ARRAY_PARAMS to generate the text for the function declaration or definition (that's why it has the type in it), and ARRAY_ARG to generate the text for the code where you pass one to a function so declared (that's why it's just 3 names - they're intended to be expressions, not names for function parameters). That means test should (?) be like this:

    void test(ARRAY_PARAMS(int, p), ARRAY_PARAMS(int, a))
    {
    }

Hopefully that makes sense.

Maybe they'd have been better off with the common C terminology of formal and actual parameters. Then you'd have ARRAY_FORMAL_PARAMS for ARRAY_PARAMS, and ARRAY_ACTUAL_PARAMS for ARRAY_ARG.