#include <stdio.h>
#include <string.h>
#include <unistd.h>
#include <sys/types.h>
#define BUFSIZE 10
 
int main(void) {
   char bufin[BUFSIZE] = "empty";
   char bufout[] = "hello"; 
   int bytesin;
   pid_t childpid;  
   int fd[2]; 
    
   if (pipe(fd) == -1) {
      perror("Failed to create the pipe"); 
      return 1; 
   } 
   bytesin = strlen(bufin);
   childpid = fork();
   if (childpid == -1) {
      perror("Failed to fork"); 
      return 1;
   }
   if (childpid)                                       /* parent code */
      write(fd[1], bufout, strlen(bufout)+1);
   else                                                 /* child code */
      bytesin = read(fd[0], bufin, BUFSIZE);
   fprintf(stderr, "[%ld]:my bufin is {%.*s}, my bufout is {%s}\n",
           (long)getpid(), bytesin, bufin, bufout); 
   return 0;
}