Define a CGAL::cpp11::thread wrapper for TBB or STD

Installation/include/CGAL/config.h

@@ -187,6 +187,10 @@
     defined(BOOST_NO_CXX11_HDR_UNORDERED_MAP)
 #define CGAL_CFG_NO_CPP0X_UNORDERED 1
 #endif
+#if defined( BOOST_NO_0X_HDR_THREAD) || \
+    defined( BOOST_NO_CXX11_HDR_THREAD)
+#define CGAL_CFG_NO_STD_THREAD 1
+#endif
 #if defined(BOOST_NO_DECLTYPE) || \
     defined(BOOST_NO_CXX11_DECLTYPE) || (BOOST_VERSION < 103600)
 #define CGAL_CFG_NO_CPP0X_DECLTYPE 1

STL_Extension/include/CGAL/thread.h

@@ -0,0 +1,105 @@
+// Copyright (c) 2018 GeometryFactory Sarl (France).
+// All rights reserved.
+//
+// This file is part of CGAL (www.cgal.org); 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 3 of the License,
+// or (at your option) any later version.
+//
+// Licensees holding a valid commercial license may use this file in
+// accordance with the commercial license agreement provided with the software.
+//
+// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
+// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
+//
+// $URL$
+// $Id$
+// SPDX-License-Identifier: LGPL-3.0+
+//
+// Author(s)     : Simon Giraudot
+
+#ifndef CGAL_THREAD_H
+#define CGAL_THREAD_H
+
+#include <CGAL/config.h>
+
+/*
+  This file defines the following:
+  - CGAL::cpp11::thread
+  - CGAL::cpp11::this_thread::sleep_for
+  - CGAL::cpp11::atomic
+  - CGAL::cpp11::chrono::seconds
+
+  It uses either TBB or STD depending on what's available: as TBB can
+  quite often override `std::thread`, it is possible that TBB will be
+  used instead of STD even if the real CXX11 `std::thread` is
+  available.
+*/
+
+#if defined(CGAL_LINKED_WITH_TBB)
+#  include <tbb/tbb_config.h>
+#  if TBB_IMPLEMENT_CPP0X
+#    include <tbb/compat/thread>
+#    include <tbb/atomic.h>
+#    include <tbb/tick_count.h>
+#    define CGAL_USE_TBB_THREADS 1
+#  else
+#    define CGAL_USE_TBB_THREADS 0
+#  endif
+#else
+#  define CGAL_USE_TBB_THREADS 0
+#endif
+
+#if !CGAL_USE_TBB_THREADS
+#  if !defined(CGAL_CFG_NO_STD_THREAD)
+#    include <thread>
+#    include <atomic>
+#    include <chrono>
+#    define CGAL_USE_STD_THREADS 1
+#  else
+#    define CGAL_USE_STD_THREADS 0
+#  endif
+#else
+#  define CGAL_USE_STD_THREADS 0
+#endif
+
+#if CGAL_USE_STD_THREADS || CGAL_USE_TBB_THREADS
+#  define CGAL_HAS_STD_THREADS // Useful define
+#endif
+
+namespace CGAL {
+
+namespace cpp11 {
+
+#if CGAL_USE_TBB_THREADS
+  using std::thread; // std::thread is declared by TBB if TBB_IMPLEMENT_CPP0X == 1
+  namespace this_thread
+  {
+    using std::this_thread::sleep_for;  // std::this_thread::sleep_for is declared by TBB if TBB_IMPLEMENT_CPP0X == 1
+  }
+  using tbb::atomic;
+  namespace chrono
+  {
+    typedef tbb::tick_count::interval_t seconds;
+  }
+#elif CGAL_USE_STD_THREADS
+  using std::thread;
+  namespace this_thread
+  {
+    using std::this_thread::sleep_for;
+  }
+  using std::atomic;
+  namespace chrono
+  {
+    typedef std::chrono::duration<double, std::ratio<1> > seconds;
+  }
+#endif
+
+} // cpp11
+
+} //namespace CGAL
+
+#undef CGAL_USE_STD_THREADS
+#undef CGAL_USE_TBB_THREADS
+
+#endif // CGAL_THREAD_H