A Simple Program that Creates a Pipe

#include <sys/types.h> #include <unistd.h> #include <stdio.h> #include <stdlib.h> /* Read characters from the pipe and echo them to stdout. */ void read_from_pipe (int file) { FILE *stream; int c; stream = fdopen (file, "r"); while ((c = fgetc (stream)) != EOF) putchar (c); fclose (stream); } /* Write some random text to the pipe. */ void write_to_pipe (int file) { FILE *stream; stream = fdopen (file, "w"); fprintf (stream, "hello, world!\n"); fprintf (stream, "goodbye, world!\n"); fclose (stream); } int main (void) { pid_t pid; int mypipe[2]; /* Create the pipe. */ if (pipe (mypipe)) { fprintf (stderr, "Pipe failed.\n"); return EXIT_FAILURE; } /* Create the child process. */ pid = fork (); if (pid == (pid_t) 0) { /* This is the child process. Close other end first. */ close (mypipe[1]); read_from_pipe (mypipe[0]); return EXIT_SUCCESS; } else if (pid < (pid_t) 0) { /* The fork failed. */ fprintf (stderr, "Fork failed.\n"); return EXIT_FAILURE; } else { /* This is the parent process. Close other end first. */ close (mypipe[0]); write_to_pipe (mypipe[1]); return EXIT_SUCCESS; } }

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