#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
int main(void)
{
int pid_1, pid_2;

printf ("ppid_1=%d.\n", getpid());

{
pid_1 = fork();
if (pid_1 == 0) printf("pid_1=%d.\n", getpid());
} 

printf ("ppid_2=%d.\n", getpid());

{
pid_2 = fork();
if (pid_2 == 0) printf("pid_2=%d.\n", getpid());
}

return 0;
}