What is C local function declaration mechanism?

Question

Local function declaration seems to be permitted in gcc, and I found a discussion on this: Is there any use for local function declarations?

However, my question is: is

Answer 1

To fix the second example you need to declare f in main with proper return type

int main(void) {
    void f(void);  // function declaration
    f(); // calling function
}  // scope of f ends here

void f(void) {} 

This way you inform compiler what to look for, and later it finds it indeed. Hope it helps.