> In my concrete example, given that FILE and DIR were classified as objects, to which of the so-called objects does F(const char*, FILE, DIR) belong? Possible answers: 1. FILE 2. DIR 3. None of them 4. Both of them 5. They stop being objects 6. New objects are created, and those own F 7.Something else

I don't think your question necessarily has an answer, but if I have to pick, I'd say (3). F is a classless method; FILE and DIR are classes; as a classless method, F cannot belong to any class, so it can't belong to FILE or DIR.

If the function was F(FILE, const char*, DIR) then F might be a method of FILE instead, if the code base is following the "this is first argument" convention.

> I don't think your question necessarily has an answer,

And why is that? Are objects and OOP not clearly defined? If you proclaim FILE and DIR to be classes, should it not be extremely clear what are their methods?

That's the problem right there, as I said it repeatedly. In C++, objects can be identified unambiguously.

Whereas in C, if you keep insisting it's OOP, the answer is whatever you want it to be. "FILE is an object, and I'll handwave away all inconvenient details that get in the way of my perception of FILE as an object". Sorry, I expect a higher level of rigour.

> F is a classless method

> FILE and DIR are classes

> If the function was F(FILE, const char, DIR) then F might be a method of FILE instead, if the code base is following the "this is first argument" convention.

The C standard library doesn't seem to follows such a convention. For example:

> fread(void , size_t, size_t, FILE );

> fgets(char, int, FILE );

> fseek(FILE , long int, int);

If FILE is a class, is fgets a method of this class? If fgets is a method of FILE, why is F in my example not a method of FILE too?