Default argument promotions in C function calls

Question

Setup

I have a few questions about the default argument promotions when calling a function in C. Here\'s section 6.5.2.2 \"Function calls\" Paragraphs 6, 7, and 8

Answer 1

Your confusion stems from a very slight misunderstanding of the terminology - both declarations and definitions can include prototypes (or not):

void func(int a, char b, float c);

That is a function declaration that includes a prototype.

void func(int a, char b, float c) { /* ... */ }

That is a function definition that includes a prototype.

"Prototyped" and "non-prototyped" are just attributes of a function type, and both declarations and definitions introduce the type of the function.

So you can have a declaration without a prototype:

void func();

or you can have a definition without a prototype (K&R C style):

void func(a, b, c)
    int a;
    char b;
    float c;
{ /* ... */ }