#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <sys/wait.h>

int
main ()
{
  int fd;
  ssize_t nbytes;
  char buf[5];

  if (mkfifo ("/tmp/myfifo", S_IRUSR | S_IWUSR | S_IWGRP) < 0
      && errno != EEXIST)
    {
      perror ("mkfifo");
      exit (-1);
    }

  if ((fd = open ("/tmp/myfifo", O_RDWR)) < 0)
    {
      perror ("open");
      exit (-1);
    }

  switch (fork ())
    {
    case -1:
      perror ("fork");
      exit (-1);
    case 0:			/* Child. */
      nbytes = read (fd, buf, 4);
      if (nbytes != 4)
	{
	  perror ("read");
	  exit (-1);
	}
      buf[4] = '\0';
      printf ("child read %d bytes: %s\n", nbytes, buf);
      if (close (fd) < 0)
	{
	  perror ("child close");
	  exit (-1);
	}
      exit (0);
    default:			/* Parent. */
      if (close (fd) < 0)
	{
	  perror ("parent close");
	  exit (-1);
	}
      printf ("parent waiting for child to read\n");
      wait (NULL);
      break;
    }
}