Thanks! Will change that too. Don't know how many will use this with C89 but since it is easy to change I'll do it.

I like them because of this reason too. That's why I wanted to use them...
But since I'm more used to C++ than to C I don't know I don't know what is wrong with this statement in C

Is the problem that I access the enum via the ANIMATION struct?
Already googled it, but found nothing usefull yet... will search more later.

But if anyone is would point out what the problem with this is I would be glad

You can actually use enum items that way? I didn't think the enum was "namespaced" into the struct itself. But then I only started using Enums after I started using C++ more often.

Hmm... when I change it to ANIMATION.MULTIPLE_BITMAPS i get a warning in msvc (C4832).
MSDN said the following:

// C4832.cpp
// compile with: /W1
struct A {
   enum { e };
};

int main() {
   return A.e;   // C4832
   // try the following line instead
   // return A::e;
}

So MSVC wants it with ::

With mingw I get an error: "...\animation_c.c|16|error: expected primary-expression before '.' token|"

Hmm... I thought that there is a way to deal with enums and structs that is valid in C and C++.

I want the code to be usable in a C as well in a C++ program. So I have to find a way that is correct in both languages.
Seems the defines are the easiest solution for now unless someone can point me in the right direction regarding this enum topic...