anonymous_pipe_server.cpp

Conexus::Pipe anonymous pipe server 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

void print_data(const Conexus::Data d);

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

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

  Conexus::init();

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

  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 */
      pipe->signal_data().connect( sigc::ptr_fun( &print_data ) );
      pipe->start();
      while ( pipe->is_running() )
        usleep(10000);

      _exit(EXIT_SUCCESS);
    }
  else
    { /* Parent writes argv[1] to pipe */
      pipe->close_read(); /* Close unused read end */

      /* Write the input string twice with a 3 second delay */
      pipe->write(data, strlen(data));
      pipe->write("\n", 2);
      sleep(3);
      pipe->write(data, strlen(data));
      pipe->write("\n", 2);

      pipe->close();          /* Reader will see EOF */
      wait(NULL);             /* Wait for child */
      exit(EXIT_SUCCESS);
    }
}

void print_data( const Conexus::Data d ) {
  for ( unsigned i = 0; i < d.size(); i++ )
    std::cout << d[i];
  std::cout << std::flush;
}