dj2@Melete:~$ cat main.c
#include <stdio.h>
#include <limits.h>
#include <stdlib.h>
main()
{
        char buf[1024];
        char *s=realpath(NULL, buf);
}
dj2@Melete:~$ gcc -o m main.c
dj2@Melete:~$ ./m
dj2@Melete:~$