Upgrade to boost 1.33.1

[lyx.git] / boost / boost / detail / lightweight_mutex.hpp

diff --git a/boost/boost/detail/lightweight_mutex.hpp b/boost/boost/detail/lightweight_mutex.hpp
index 1310da375596714da19547580cc3f591ac8e70a4..a0936cbb95ad4c52ba2c283fd1ff9c9563c3232e 100644 (file)
--- a/boost/boost/detail/lightweight_mutex.hpp
+++ b/boost/boost/detail/lightweight_mutex.hpp
@@ -1,85 +1,38 @@
 #ifndef BOOST_DETAIL_LIGHTWEIGHT_MUTEX_HPP_INCLUDED
 #define BOOST_DETAIL_LIGHTWEIGHT_MUTEX_HPP_INCLUDED
 
-#if _MSC_VER >= 1020
-#pragma once
+// MS compatible compilers support #pragma once
+
+#if defined(_MSC_VER) && (_MSC_VER >= 1020)
+# pragma once
 #endif
 
 //
 //  boost/detail/lightweight_mutex.hpp - lightweight mutex
 //
-//  Copyright (c) 2002 Peter Dimov and Multi Media Ltd.
+//  Copyright (c) 2002, 2003 Peter Dimov and Multi Media Ltd.
 //
-//  Permission to copy, use, modify, sell and distribute this software
-//  is granted provided this copyright notice appears in all copies.
-//  This software is provided "as is" without express or implied
-//  warranty, and with no claim as to its suitability for any purpose.
+// Distributed under the Boost Software License, Version 1.0. (See
+// accompanying file LICENSE_1_0.txt or copy at
+// http://www.boost.org/LICENSE_1_0.txt)
 //
 //  typedef <unspecified> boost::detail::lightweight_mutex;
 //
-//  boost::detail::lightweight_mutex meets a subset of the Mutex concept
-//  requirements: http://www.boost.org/libs/thread/doc/mutex_concept.html#Mutex
-//
-//  * Used by the smart pointer library
-//  * Performance oriented
-//  * Header-only implementation
-//  * Small memory footprint
-//  * Not a general purpose mutex, use boost::mutex, CRITICAL_SECTION or
-//    pthread_mutex instead.
-//  * Never spin in a tight lock/do-something/unlock loop, since
-//    lightweight_mutex does not guarantee fairness.
-//  * Never keep a lightweight_mutex locked for long periods.
-//
-//  The current implementation can use a pthread_mutex, a CRITICAL_SECTION,
-//  or a platform-specific spinlock.
+//  boost::detail::lightweight_mutex is a header-only implementation of
+//  a subset of the Mutex concept requirements:
 //
-//  You can force a particular implementation by defining BOOST_LWM_USE_PTHREADS,
-//  BOOST_LWM_USE_CRITICAL_SECTION, or BOOST_LWM_USE_SPINLOCK.
+//  http://www.boost.org/doc/html/threads/concepts.html#threads.concepts.Mutex
 //
-//  If neither macro has been defined, the default is to use a spinlock on Win32,
-//  and a pthread_mutex otherwise.
+//  It maps to a CRITICAL_SECTION on Windows or a pthread_mutex on POSIX.
 //
-//  Note that a spinlock is not a general synchronization primitive. In particular,
-//  it is not guaranteed to be a memory barrier, and it is possible to "livelock"
-//  if a lower-priority thread has acquired the spinlock but a higher-priority
-//  thread is spinning trying to acquire the same lock.
-//
-//  For these reasons, spinlocks have been disabled by default except on Windows,
-//  where a spinlock can be several orders of magnitude faster than a CRITICAL_SECTION.
-
-
-//  Note: lwm_linux.hpp has been disabled by default; see the comments
-//        inside for more info.
-
 
 #include <boost/config.hpp>
 
-//  Note to implementors: if you write a platform-specific spinlock
-//  for a platform that supports pthreads, be sure to test its performance
-//  against the pthreads-based version using shared_ptr_timing_test.cpp and
-//  shared_ptr_mt_test.cpp. Custom versions are usually not worth the trouble
-//  _unless_ the performance gains are substantial.
-//
-//  Be sure to compare against a "real" pthreads library;
-//  shared_ptr_timing_test.cpp will compile succesfully with a stub do-nothing
-//  pthreads library, since it doesn't create any threads.
-
-#ifndef BOOST_HAS_THREADS
-#  include <boost/detail/lwm_nop.hpp>
-#elif defined(BOOST_LWM_USE_SPINLOCK) && defined(BOOST_USE_ASM_ATOMIC_H)
-#  include <boost/detail/lwm_linux.hpp>
-#elif defined(BOOST_LWM_USE_CRITICAL_SECTION)
-#  include <boost/detail/lwm_win32_cs.hpp>
-#elif defined(BOOST_LWM_USE_PTHREADS)
-#  include <boost/detail/lwm_pthreads.hpp>
+#if !defined(BOOST_HAS_THREADS)
+# include <boost/detail/lwm_nop.hpp>
 #elif defined(WIN32) || defined(_WIN32) || defined(__WIN32__)
-#  include <boost/detail/lwm_win32.hpp>
-#elif defined(BOOST_LWM_USE_SPINLOCK) && defined(__sgi)
-#  include <boost/detail/lwm_irix.hpp>
-#elif defined(BOOST_LWM_USE_SPINLOCK) && defined(__GLIBCPP__)
-#  include <boost/detail/lwm_gcc.hpp>
+#  include <boost/detail/lwm_win32_cs.hpp>
 #elif defined(BOOST_HAS_PTHREADS)
-#  define BOOST_LWM_USE_PTHREADS
 #  include <boost/detail/lwm_pthreads.hpp>
 #else
 // Use #define BOOST_DISABLE_THREADS to avoid the error