accessing a static function

I am trying indirectly accessing a static function using function pointer within a program. , I've encountered errors that I'm struggling to resolve.

main.c

Code:

---

#include<stdio.h>

void (*fp)();


static void foo()
{
        printf("Welcome \n");
       
}


int main()
{
    fp = &foo;
       
        return 0;

}

---

file1.c

Code:

---

extern void (*fp)();

fp();

---

Output

Code:

---

file1.c:3:1: warning: data definition has no type or storage class fp();
 ^~
file1.c:3:1: warning: type defaults to 'int' in declaration of 'fp' [-Wimplicit-int]
file1.c:3:1: error: 'fp' redeclared as different kind of symbol
file1.c:1:15: note: previous declaration of 'fp' was here

 extern void (*fp)();

---

Works for me.

Code:

---

$ cat foo.c
#include<stdio.h>

void bar();

void (*fp)();

static void foo()
{
    printf("Welcome \n");
}

int main()
{
    fp = &foo;
    bar();
    return 0;
}
$ cat bar.c
#include <stdio.h>
extern void (*fp)();

void bar() {
    fp();
}
$ gcc foo.c bar.c
$ ./a.out
Welcome

---

But what you posted of file1.c is broken to the point of useless, so it's impossible to say for sure what you might be doing wrong.

Quote:

---

Originally Posted by Salem

Works for me.

Code:

---

$ cat foo.c
#include<stdio.h>

void bar();

void (*fp)();

static void foo()
{
    printf("Welcome \n");
}

int main()
{
    fp = &foo;
    bar();
    return 0;
}
$ cat bar.c
#include <stdio.h>
extern void (*fp)();

void bar() {
    fp();
}
$ gcc foo.c bar.c
$ ./a.out
Welcome

---

But what you posted of file1.c is broken to the point of useless, so it's impossible to say for sure what you might be doing wrong.

---

hi as i am in process of learning, i think there is one issue with his code, i would say his file1.c 3rd row acts as redeclaration as it is without type specified it is defaulted to int, i am not sure but he probably can't call fp(); in global scope of file1.c module. What do you think?

Quote:

---

Originally Posted by Salem

Works for me..

---

When I ran your code on my window PC I got output "The system cannot execute the specified program"

Code:

---

command
C:\Users\Kittu\Desktop\C Example>gcc -o hello main.c file1.c


C:\Users\Kittu\Desktop\C Example>hello
The system cannot execute the specified program.

---

I used my file names

You're on windows.
Try calling it hello.exe

Quote:

---

Originally Posted by Salem

You're on windows.
Try calling it hello.exe

---

Yes It works

I don't understand why need of bar function in your code ?

why it can't be like

Code:

---

externvoid(*fp)();
fp();

---

> why it can't be like
Why would you think that?

You can't just call a function randomly from a line like that.

It has to be inside a function definition.

As it stands, it looks like some old-style function declaration - declare fp() as a function (implicitly) returning int, and taking unspecified parameters.

It certainly doesn't call the function.