GCC program undefined reference to function (multiple folders)

Question

I'm running into undefined reference to function during compilation. This is my program:

main.c:

#include <stdio.h>
#include "SSD/ssd.h"

int main(void)
{
    printf("%d\n",f());
    return 0;
}

SSD/ssd.h:

#ifndef SSD_H
#define SSD_H

int f();

#endif // SSD_H

SSD/ssd.c:

#include "ssd.h"

int f(){
    return 4;
}

files ssd.h and ssd.c Are in folder SSD and file main.c and folder SSD are in the same folder. During compilation however I get:

[miku@MikuToshiba Lab5]$ gcc main.c -o run
/tmp/cc9X2i1H.o: In function `main':
main.c:(.text+0xa): undefined reference to `f'
collect2: error: ld returned 1 exit status

I'm running Fedora23

Answer 1

You only build with main.c , even though SSD/ssd.c contains code as well.

Include it in your building process:

gcc SSD/ssd.c main.c -o run