can I make functions with unresolved dependency in C?

Question

what is the SHORTEST or Easiest way to solve the following dependency problem. Given, I have to keep xx in a separate file.

file1.h

    static inline void xx(){
      yy();//yy is not defined in this file but defined in file2.c;
    }

file2.c

  #include "file1.h"
  void yy(){
     printf("Hello");
   }

    void main(){
      xx();
    }

Compiler error in file1 yy not defined.

It is actually defined in the same translation unit, it is just not declared prior use. — user7860670, Oct 26 '19 at 15:14
Functions (and variables, and types, and structures, etc.) needs to be *declared* before they are used. — Some programmer dude, Oct 26 '19 at 15:17

Aykhan Hagverdili · Accepted Answer · 2019-10-26T15:24:29.077

1

A declaration is required but not a definition:

// file1.h

static inline void xx() {
    void yy(); // Just a declaration

    yy(); 
}

// file2.c

#include "file1.h"
void yy() {
    printf("Hello");
}

int main() { // void main is not legal C
    xx(); // Works fine.
}

edited Oct 26 '19 at 15:24

answered Oct 26 '19 at 15:18

Aykhan Hagverdili

score 1 · Answer 2 · answered Oct 26 '19 at 15:18

1

Pre-Declare yy.

file1.h

+++ void yy();

    static inline void xx(){
      yy();
    }

answered Oct 26 '19 at 15:18

datenwolf

score 1 · Answer 3 · answered Oct 26 '19 at 15:20

1

Just function declaration prior using will solve the issue.

static inline void xx() {
    void yy();
    yy();  // no more yy is not declared
}

answered Oct 26 '19 at 15:20

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