anonymous_pipe.cpp

Conexus::Pipe anonymous pipe example

/***************************************************************************
 *   Copyright (C) 2001 by Rick L. Vinyard, Jr.                            *
 *   rvinyard@cs.nmsu.edu                                                  *
 *                                                                         *
 *   This file is part of the conexus library.                             *
 *                                                                         *
 *   The conexus library is free software; you can redistribute it and/or  *
 *   modify it under the terms of the GNU General Public License version 3 *
 *   as published by the Free Software Foundation.                         *
 *                                                                         *
 *   The conexus library is distributed in the hope that it will be        *
 *   useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
 *   of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU   *
 *   General Public License for more details.                              *
 *                                                                         *
 *   You should have received a copy of the GNU General Public License     *
 *   along with this software. If not see <http://www.gnu.org/licenses/>.  *
 ***************************************************************************/

#include <conexus.h>
#include <iostream>

#include <sys/wait.h>
#include <assert.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

// This is the canonical pipe example program found in man (2) pipe
// rewritten to illustrate pipes in the Conexus library

int
main ( int argc, char *argv[] )
{
  const char* data = "Hello World!!!";
  Conexus::init();

  Conexus::Pipe::pointer pipe = Conexus::Pipe::create();
  Conexus::Data d;
  pid_t cpid;

  if ( argc > 1 ) data = argv[1];

  pipe->open();

  cpid = fork();
  if ( cpid == -1 )
  {
    perror ( "fork" );
    exit ( EXIT_FAILURE );
  }

  if ( cpid == 0 )
  {
    /* Child reads from pipe */
    pipe->close_write(); /* Close unused write end */
    try
    {
      while ( d = pipe->read ( 1 ) )
        std::cout << d[0];
    }
    catch ( Conexus::exception::read::disconnected ) { }
    std::cout << std::endl;
    _exit ( EXIT_SUCCESS );
  }
  else
  {
    /* Parent writes argv[1] to pipe */
    pipe->close_read(); /* Close unused read end */
    pipe->write ( data, strlen ( data ) );
    pipe->close();          /* Reader will see EOF */
    wait ( NULL );          /* Wait for child */
    exit ( EXIT_SUCCESS );
  }
}