#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
int main(void){
   printf("Process ID: %ld\n", (long)getpid());
   printf("Parent process ID: %ld\n", (long)getppid());
   printf("Owner user ID: %ld\n", (long)getuid());
   printf("Effective user ID: %ld\n", (long)geteuid());
   return 0;
}