Nested function in C

Question

Can we have a nested function in C? What is the use of nested functions? If they exist in C does their implementation differ from compiler to compiler?

Answer 1

Or you can be smart about it and use the preprocessor in your advantage (source.c):

#ifndef FIRSTPASS
#include 

//here comes your "nested" definitions
#define FIRSTPASS
#include "source.c"
#undef FIRSTPASS

main(){
#else
    int global = 2;
    int func() {printf("%d\n", global);}
#endif
#ifndef FIRSTPASS
    func();}
#endif