# include <stdio.h>

int main(void)
{
        int GETUID=getuid(), GETGID=getgid();
        int GETEUID=geteuid(), GETEGID=getegid();
        int ISSETUGID=issetugid();

        printf("Your real user ID is %d\n", GETUID);
        printf("Your real group ID is %d\n", GETGID);
        printf("Your effective user ID is %d\n", GETEUID);
        printf("Your effective group ID is %d\n", GETEGID);

        if (ISSETUGID == 1)
         {
           printf("issetugid() says this program is SUID\n");
         }
        else
         {
           printf("issetugid() says this program is not SUID\n");
         }

        return 0;
}