ThreadSema1Example

    // ------------------------------- //
    // -------- Start of File -------- //
    // ------------------------------- //
    // ----------------------------------------------------------- //
    // C++ Source Code File Name: testprog.cpp
    // Compiler Used: MSVC, BCC32, GCC, HPUX aCC, SOLARIS CC
    // Produced By: DataReel Software Development Team
    // File Creation Date: 03/25/2000
    // 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

    Simple test program demonstrating the basic operation of the
    gxThread class using semaphores
    */
    // ----------------------------------------------------------- //
    #include "gxdlcode.h"

    #if defined (__USE_ANSI_CPP__) // Use the ANSI Standard C++ library
    #include <iostream>
    using namespace std; // Use unqualified names for Standard C++ library
    #else // Use the old iostream library by default
    #include <iostream.h>
    #endif // __USE_ANSI_CPP__

    #include <stdlib.h>
    #include "gxthread.h"
    #include "gxsema.h"

    #ifdef __MSVC_DEBUG__
    #include "leaktest.h"
    #endif

    // Global semaphores objects
    gxSemaphore child_counter;
    gxSemaphore parent_counter;

    // Class derived from the abstract gxThread base class
    class MessageClass : public gxThread
    {
    public:
      MessageClass() { }
      ~MessageClass() { }

    public:
      char *message;

    private: // Base class interface
      void *ThreadEntryRoutine(gxThread_t *thread);
    };

    void *MessageClass::ThreadEntryRoutine(gxThread_t *thread)
    {
      cout << message << "\n" << flush;

      // The up operation increments the semaphore
      parent_counter.SemaphorePost();
      child_counter.SemaphorePost();
      return 0;
    }

    int main()
    {
    #ifdef __MSVC_DEBUG__
      InitLeakTest();
    #endif

      MessageClass t;

      char *message1 = "Test message 1";
      char *message2 = "Test message 2";

      parent_counter.SemaphoreWait();

      child_counter--; // Semaphore value now 0
      child_counter--; // Semaphore value now -1

      // The child_counter now must be incremented 2 times
      // for a thread blocked on it to be released

      t.message = message1;
      gxThread_t *tptr1 = t.CreateThread();

      // The wait operation blocks the thread if the semaphore
      // has a value less than or equal to zero.
      parent_counter.SemaphoreWait();

      t.message = message2;
      gxThread_t *tptr2 = t.CreateThread();

      // Force the parent thread to block until both children have
      // printed their message and executed the following semaphore
      // up function.
      child_counter.SemaphoreWait();

      // Wait for the last thread to print its message before exiting
      t.sSleep(1);

      cout << "\n";

      // Prevent memory leaks
      delete tptr1;
      delete tptr2;

      return 0;
    }
    // ----------------------------------------------------------- //
    // ------------------------------- //
    // --------- End of File --------- //
    // ------------------------------- //