text: ///////////////////////////////////////////////////////////////////////////
  //
  // Copyright (c) 2005-2012, Industrial Light & Magic, a division of Lucas
  // Digital Ltd. LLC
  // 
  // All rights reserved.
  // 
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are
  // met:
  // *       Redistributions of source code must retain the above copyright
  // notice, this list of conditions and the following disclaimer.
  // *       Redistributions in binary form must reproduce the above
  // copyright notice, this list of conditions and the following disclaimer
  // in the documentation and/or other materials provided with the
  // distribution.
  // *       Neither the name of Industrial Light & Magic nor the names of
  // its contributors may be used to endorse or promote products derived
  // from this software without specific prior written permission. 
  // 
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
  // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
  // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
  // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  //
  ///////////////////////////////////////////////////////////////////////////
  
  #ifndef INCLUDED_ILM_THREAD_H
  #define INCLUDED_ILM_THREAD_H
  
  //-----------------------------------------------------------------------------
  //
  //	class Thread
  //
  //	Class Thread is a portable interface to a system-dependent thread
  //	primitive.  In order to make a thread actually do something useful,
  //	you must derive a subclass from class Thread and implement the
  //	run() function.  If the operating system supports threading then
  //	the run() function will be executed int a new thread.
  //
  //	The actual creation of the thread is done by the start() routine
  //	which then calls the run() function.  In general the start()
  //	routine should be called from the constructor of the derived class.
  //
  //	The base-class thread destructor will join/destroy the thread.
  //
  //	IMPORTANT: Due to the mechanisms that encapsulate the low-level
  //	threading primitives in a C++ class there is a race condition
  //	with code resembling the following:
  //
  //	    {
  //		WorkerThread myThread;
  //	    } // myThread goes out of scope, is destroyed
  //	      // and the thread is joined
  //
  //	The race is between the parent thread joining the child thread
  //	in the destructor of myThread, and the run() function in the
  //	child thread.  If the destructor gets executed first then run()
  //	will be called with an invalid "this" pointer.
  //
  //	This issue can be fixed by using a Semaphore to keep track of
  //	whether the run() function has already been called.  You can
  //	include a Semaphore member variable within your derived class
  //	which you post() on in the run() function, and wait() on in the
  //	destructor before the thread is joined.  Alternatively you could
  //	do something like this:
  //
  //	    Semaphore runStarted;
  //
  //	    void WorkerThread::run ()
  //	    {
  //		runStarted.post()
  //		// do some work
  //		...
  //	    }
  //
  //	    {
  //		WorkerThread myThread;
  //		runStarted.wait ();    // ensure that we have started
  //				       // the run function
  //	    } // myThread goes out of scope, is destroyed
  //	      // and the thread is joined
  //
  //-----------------------------------------------------------------------------
  
  #include "IlmThreadConfig.h"
  #include "IlmThreadExport.h"
  #include "IlmThreadNamespace.h"
  
  #if ILMTHREAD_THREADING_ENABLED
  #include <thread>
  #endif
  
  ILMTHREAD_INTERNAL_NAMESPACE_HEADER_ENTER
  
  //
  // Query function to determine if the current platform supports
  // threads AND this library was compiled with threading enabled.
  //
  
  ILMTHREAD_EXPORT bool supportsThreads ();
  
  
  class Thread
  {
    public:
  
      ILMTHREAD_EXPORT Thread ();
      ILMTHREAD_EXPORT virtual ~Thread ();
  
      ILMTHREAD_EXPORT void         start ();
      ILMTHREAD_EXPORT virtual void run () = 0;
  
      //
      // wait for thread to exit - must be called before deleting thread
      //
      void join();
      bool joinable() const;
  
    private:
  
  #if ILMTHREAD_THREADING_ENABLED
      std::thread _thread;
  #endif
  
      Thread &operator= (const Thread& t) = delete;
      Thread &operator= (Thread&& t) = delete;
      Thread (const Thread& t) = delete;
      Thread (Thread&& t) = delete;
  };
  
  
  ILMTHREAD_INTERNAL_NAMESPACE_HEADER_EXIT
  
  #endif // INCLUDED_ILM_THREAD_H
  