forward declarations of nested functions in GNU C

[bostjanv]

Hello,
I encountered a problem when I tried to write a program in GNU C, which allows nested (local) functions to be used. I wasn't able to make a forward declaration to work. The problem is illustrated with the following short program

// GNU c program demonstrating problem with forward declarations 
// of nested functions.
// Compiler produces error "static-declaration follows non-static 
//declaration";
// when I place the keyword "static" in front of "void Inner2();", I still
// get an error
// Program was tested on gcc (Debian 8.3.0-6) as well as on
// gcc (Rev2, Built by MSYS2 project) 9.2.0
#include<stdio.h>

void Outer(){
  void Inner2(); // "non-static declaration"
  void Inner1(){
    Inner2();
  }
  void Inner2(){ // "static-declaration"
    printf("%s","Hello World!");
  }

  Inner1();
}

int main(){
  Outer();
}

I would appreciate any information how to make forward declarations of nested functions work.
Regards,
bostjanv

[john.c]

There is no standard answer as this is non-standard functionality.
However, for gcc you need to put the keyword "auto" in front of the forward declaration of a nested function.

[bostjanv]

Thanks a lot! Your answer worked. And Happy New Year.
bostjanv