[SOLVED] struct declared in tools.h and defined in tools.c. Can't link them to main.c

Issue

file tools.h:

//some macro definitions

struct name;

//other function prototypes

---

file tools.c:

#include "tools.h"

struct name
{
    FILE *src;
    int value;
}


//definitions of functions declared in tools.h

---

file main.c:

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

int main()
{
    struct name *ptr;
    ptr = malloc(sizeof(struct name));
    ptr->FILE = fopen(filename, "r");
    ptr->value = 12;
    ...
}

---

1. At first, I built tools.o by using:
   $ gcc tools.c -c
   Without any error or warning, tools.o was built in the current directory.

2. Now, I tried to build executable by using:
   $ gcc main.c tools.o -o exe
   and I got errors of same type (all the errors were of same type, caused due to accessing the struct element). Here's the sample of that error I got:

main.c: In function ‘main’:
main.c:17:22: error: invalid use of undefined type ‘struct name’
   17 |   buffer = malloc(ptr->value+1);

---

Please explain why this happened and what wrong I did while linking or in my code.

Solution

tools.h file

#ifndef TOOLS_H
#define TOOLS_H

#include <stdio.h>

struct name
{
    FILE *src;
    int value;
};

int foo(struct name*);
struct name *bar(double, FILE*, const char *);  //prototypes of functions defined in tools.c
#endif

tools.c

#include "tools.h"

int foo(struct name*)
{
   /* ... */
}

struct name *bar(double, FILE*, const char *)
{
   /* ... */
}

Answered By - 0___________

Answer Checked By - Timothy Miller (WPSolving Admin)