RecvUNIXExample

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    // -------- Start of File -------- //
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    // C++ Source Code File Name: r_unix.cpp
    // C++ Compiler Used: MSVC, BCC32, GCC, HPUX aCC, SOLARIS CC
    // Produced By: DataReel Software Development Team
    // File Creation Date: 09/20/1999
    // Date Last Modified: 06/17/2016
    // Copyright (c) 2001-2016 DataReel Software Development
    // ----------------------------------------------------------- //
    // ------------- Program Description and Details ------------- //
    // ----------------------------------------------------------- //
    /*
    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 of the License, or (at your option) any later version.

    This 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
    USA

    Code used by UNIX systems to read data from a serial port using
    a signal handler.
    */
    // ----------------------------------------------------------- //
    #include "gxdlcode.h"

    #include <fcntl.h>

    // #ifndef __USE_SIGNAL_IO__
    // #define __USE_SIGNAL_IO__
    // #endif

    #ifndef __USE_SIGNAL_IO__ // Do not interrupt driven I/O
    void SerialRead(gxSerialComm *dev, char *dumpfile = 0)
    {
      DiskFileB outfile;
      if(dumpfile) {
        cout << "Writing output to the " << dumpfile << " file" << "\n" << flush;
        outfile.df_Create(dumpfile);
        if(!outfile) {
          cout << "\n" << flush;
          cout << "Cannot open the: " << dumpfile << " capture file"
    	   << "\n" << flush;
          cout << "Exiting..." << "\n" << flush;
          cout << "\n" << flush;
          return;
        }
      }

      cout << "Waiting to receive..." << "\n" << flush;
      cout << "Press Ctrl C to terminate." << "\n" << flush;

      const int rxBufferLen = 255;
      char buf[rxBufferLen];

      // Loop while waiting for input
      while(1) {
        usleep(100000); // Allow for I/O recovery time
        dev->RawRead((char *)buf, rxBufferLen);
        if(dev->BytesRead() > 0) {
          buf[dev->BytesRead()] = 0; // Null terminate the string
          if(dumpfile) { // Capture data to a file
    	outfile.df_Write((char *)buf, dev->BytesRead());
    	outfile.df_Flush();
          }
          else { // Write the data to the console
    	cout << buf << flush;
          }
        }
      }
    }

    #else // Using interrupt driven I/O
    #include <sys/signal.h>

    int comSTOP=0;
    void signal_handler_IO(int status);  // Signal handler
    int wait_flag=1;  // true while no signal received

    void SerialRead(gxSerialComm *dev, char *dumpfile = 0)
    {
      DiskFileB outfile;
      if(dumpfile) {
        cout << "Writing output to the " << dumpfile << " file" << "\n" << flush;
        outfile.df_Create(dumpfile);
        if(!outfile) {
          cout << "\n" << flush;
          cout << "Cannot open the: " << dumpfile << " capture file"
    	   << "\n" << flush;
          cout << "Exiting..." << "\n" << flush;
          cout << "\n" << flush;
          return;
        }
      }

      struct sigaction saio; // Signal action
      const int rxBufferLen = 255;
      char buf[rxBufferLen];

      // Install the signal handler before making the device asynchronous
      saio.sa_handler = signal_handler_IO;
      saio.sa_flags = 0;
      sigaction(SIGIO, &saio, 0);

      // Allow this process to receive SIGIO
    #if defined (FASYNC) // ASYNC I/O is a BDS feature
      // A SIGIO signal will be sent whenever input or
      // output becomes possible on this file descriptor.
      fcntl(dev->DeviceHandle(), F_SETOWN, getpid());
      fcntl(dev->DeviceHandle(), F_SETFL, FASYNC);

    #elif defined (FIOSSAIOSTAT) // HPUX specific
      // Set the process ID that will receive the SIGIO signals
      ioctl(dev->DeviceHandle(), FIOSSAIOOWN, dev->GetTermIOS());
      ioctl(dev->DeviceHandle(), FIOSSAIOSTAT, dev->GetTermIOS());

    #else
    #error Cannot receive SIGIO signals using ASYNC IO
    #endif

      cout << "Waiting to receive..." << "\n" << flush;
      cout << "Press Ctrl C to terminate." << "\n" << flush;

      // Loop while waiting for input
      while(comSTOP == 0) {
        // After receiving SIGIO check the wait_flag to see if input
        // is available and can be read
        if(wait_flag == 0) {
          if(dev->RawRead((char *)buf, 255) < 0) {
    	// Stop loop if an error occurs
    	cerr << "\n" << flush;
    	cerr << "Read error!" << "\n" << flush;
    	cerr << "Exiting..." << "\n" << flush;
    	comSTOP = 1;
          }
          buf[dev->BytesRead()] = 0; // Null terminate the string
          if(dumpfile) { // Capture data to a file
    	outfile.df_Write((char *)buf, dev->BytesRead());
    	outfile.df_Flush();
          }
          else { // Write the data to the console
    	cout << buf << flush;
          }
          wait_flag = 1; // Wait for new input
        }
      }
    }

    void signal_handler_IO(int status)
    // Signal handler. Sets wait_flag to 0, to indicate the above loop that
    // characters have been received.
    {
      cout.flush();
      wait_flag = 0;
    }

    #endif // __USE_SIGNAL_IO__
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