books/apue/pipe.c

   1 #include <stdio.h>
   2 #include <string.h>
   3 #include <unistd.h>
   4 #include <stdlib.h>
   5
   6 int main(int argc, char *argv[])
   7 {
   8         pid_t pid;
   9         int err, n, fd[2];
  10         char line[1024];
  11
  12         err = pipe(fd);
  13         if (err) {
  14                 perror("pipe()");
  15                 exit(1);
  16         }
  17
  18         pid = fork();
  19         if (pid < 0) {
  20                 perror("fork()");
  21                 exit(1);
  22         } else if (!pid) {
  23                 /* Child */
  24                 close(fd[1]);
  25                 memset(line, '\0', sizeof(line));
  26                 n = read(fd[0], line, sizeof(line));
  27                 write(STDOUT_FILENO, line, n);
  28         } else {
  29                 /* Parent */
  30                 close(fd[0]);
  31                 write(fd[1], "hello world!\n", 13);
  32         }
  33
  34         exit(0);
  35 }