/* * ids.c - Print UIDs and GIDs */#include <stdio.h>#include <unistd.h>#include <stdlib.h>int main(void){    printf("Real user ID: %d\n", getuid());    printf("Effective user ID: %d\n", geteuid());    printf("Real group ID: %d\n", getgid());    printf("Effective group ID: %d\n", getegid());    exit(EXIT_SUCCESS);}