Scope of typedefs

Question

I am not at a computer so cannot test this at the moment but have some code to review. I'm still somewhat in a C++ mindframe unfortunatley.

So, when a typedef is declared within a C source file what is its scope? I am aware that to make functions and variables only available within the same translation unit you need to make them static and I was wondering if this is the same for typedefs?

Answer 1

Here is an example showing typedef and scope:

Click to copy

typedef int foo_t;

foo_t x = 1;

double bar(double x) {
    typedef double foo_t;
    foo_t y = 2.0;
    return y + 3.14156;
}

foo_t z = 1;

Answer 2

Typedefs are declarations. If you have a typedef in a C file, no other C file will be aware of that since they are compiled indepedendly of each other.

For a typedef in a header, it will of course be visible from all C files that include it.