Programmation systéme en C

lami20j@debian:~/trash$ cat pid.c
#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#include<errno.h>

int main ()
{
  pid_t pid_fils;

  do {
    pid_fils = fork ();
  } while (pid_fils == -1 && errno == EAGAIN);

  switch (pid_fils) {
  case -1:
    fprintf (stderr, "Erreur fork() : %d\n", errno);
    return 1;
  case 0: /* processus fils */
    fprintf (stdout, "Fils : PID = %ld, Père = %ld\n",
             (long) getpid (), (long) getppid ());
    break;
  default: /*processus père */
    fprintf (stdout, "Père : PID = %ld ; PPID = %ld, Fils : PID = %ld\n",
             (long) getpid (), (long) getppid (), (long) pid_fils);
    break;
  }
  return 0;
}
lami20j@debian:~/trash$ gcc pid.c -o pid
lami20j@debian:~/trash$ ./pid
Fils : PID = 3387, Père = 3386
Père : PID = 3386 ; PPID = 2957, Fils : PID = 3387
lami20j@debian:~/trash$ echo $$
2957
lami20j@debian:~/trash$