What is a "static" function?

Question

The question was about plain [tag:C] functions, not [tag:C++] `static` methods, as clarified in comments.Ok, I understand what a `static` variable is, but what is a `static` function?And why is it that if I declare a function, let's say `void print_matrix`, in let's say `a.c` (WITHOUT `a.h`) and include `"a.c"` - I get `"print_matrix@@....) already defined in a.obj"`, BUT if I declare it as `static void print_matrix` then it compiles?**UPDATE** Just to clear things up - I know that including `.c` is bad, as many of you pointed out. I just do it to temporarily clear space in `main.c` until I have a better idea of how to group all those functions into proper `.h` and `.c` files. Just a temporary, quick solution.

Answer 1

In C a static function is one that is only usable by other functions within the same translation unit, usually meaning the same source file. I have seen static functions used in C source code to allow reuse of the same function name in different parts of the code but this, in my view, is rarely good programming practice.