#include <sys/types.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>

int main()
{
   int fd[2], result;

   size_t size;
   char resstring[14];

   if (pipe(fd) < 0)
   {
      printf("Can\'t open pipe\n");
      exit(-1);
   }

   result = fork();

   if (result < 0)
   {
      printf("Can\'t fork child\n");
      exit(-1);
   }
   else if (result > 0)
   {

      /* Parent process */

      close(fd[0]);

      size = write(fd[1], "Hello, world!", 14);

      if (size != 14)
      {
         printf("Can\'t write all string to pipe\n");
         exit(-1);
      }

      close(fd[1]);
      printf("Parent exit\n");
   }
   else
   {

      /* Child process */

      close(fd[1]);
      size = read(fd[0], resstring, 14);

      if (size < 0)
      {
         printf("Can\'t read string from pipe\n");
         exit(-1);
      }

      printf("Child exit, resstring:%s\n", resstring);

      close(fd[0]);
   }

   return 0;
}