redefinition of typedef

Question

I am possibly doing this incorrectly and this is much a question about why it works in one compiler and not the other.

I have a large C application, and I am

Answer 1

You are defining multiple times the same thing.

You can spread it across multiple header files just have to make sure that there is some B seen before struct _A is defined.

This code works:

#include 

typedef struct _B B;
typedef struct _A A;

struct _A {
    double a;
    B *b;
};

struct _B {
    int c;
};

void function_do_something(A* a, B* b)
{
    printf("a->a (%f) b->c (%d)\n", a->a, b->c);
}

int main()
{
   A a;
   B b;

  a.a = 3.4;
  b.c = 34;

  function_do_something(&a, &b);

  return 0;
}

Output:

> ./x
a->a (3.400000) b->c (34)

EDIT: updated for C

EDIT 2: spread into multiple header files

b.h:

#ifndef B_H
#define B_H

struct _B {
    int c;
};

#endif

a.h:

#ifndef A_H
#define A_H

typedef struct _B B;

struct _A {
    double a;
    B *b;
};

typedef struct _A A;

#endif

main.c:

#include 

#include "a.h"
#include "b.h"

void function_do_something(A* a, B* b)
{
    printf("a->a (%f) b->c (%d)\n", a->a, b->c);
}

int main()
{
   A a;
   B b;

  a.a = 3.4;
  b.c = 34; 

  function_do_something(&a, &b);

  return 0;
}