Including header files in Visual Studio 2012

Question

I have a problem with Visual Studio 2012

I want to include one header file in other and then to include the second header file in .c file. I want to define a constant in first header file and use its value in c file. I think this is possible because it is done in standart libraries

When I do this compiler is sending an error message:

1>C:\\Users\\sotfware\\Desktop\\ConsoleApplication4\\Debug\\ConsoleApplication4.exe : fatal error LNK1169: one or more multiply defined symbols found

Answer 1

Put the definitions (body) of the functions in a regular C file and only the declarations in the header files. Let's say I have these functions:

void PrintHelloWorld(void)
{
      printf("Hello World\n");
}

void PrintHelloWorld2(void)
{
      printf("Hello World");
}

Then my C file would stay this ^^ but the Header file should be:

void PrintHelloWorld();
void PrintHelloWorld2();

As I remember, I think you should declare the constant in the header file.

Answer 2

I think it's OK. Maybe you can show more details about your problem.

---

First header (ah):

#ifndef A_H
#define A_H

const int i = 5;

#endif

---

Second header (bh):

#ifndef B_H
#define B_H

#include "a.h"

#endif

---

source file:

#include <stdio.h>
#include "b.h"

main() {
  printf("%d\n", i);
  exit(0);
}