drd/tests/fork.c

   1 #include <stdio.h>
   2 #include <pthread.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <unistd.h>
   6
   7 static pthread_t tid[2];
   8
   9 static void *startproc(void *arg)
  10 {
  11   pid_t pid;
  12   char *argv[] = { "/bin/ls", "/bin/ls", NULL };
  13
  14   if ((pid = fork()) == -1) {
  15     perror("fork error");
  16   } else if (pid == 0) {
  17     dup2(2, 1);    // redirect stdout to stderr
  18     execv(argv[0], argv); // child
  19   }
  20
  21   return NULL;
  22 }
  23
  24 int main(int argc, char **argv)
  25 {
  26   // No arguments means serialize the fork() calls. One argument means perform
  27   // both fork() calls concurrently.
  28   int serialize_fork = argc == 1;
  29   int i = 0;
  30   int err;
  31
  32   for (i = 0; i < 2; i++) {
  33     err = pthread_create(&tid[i], NULL, &startproc, NULL);
  34     if (err != 0)
  35       perror("pthread_create()");
  36     if (serialize_fork)
  37       pthread_join(tid[i], NULL);
  38   }
  39   if (!serialize_fork) {
  40     for (i = 0; i < 2; i++)
  41       if (tid[i])
  42         pthread_join(tid[i], NULL);
  43   }
  44   return 0;
  45 }