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authorRemko Tronçon <git@el-tramo.be>2009-06-01 08:48:42 (GMT)
committerRemko Tronçon <git@el-tramo.be>2009-06-01 09:24:28 (GMT)
commit2812bddd81f8a1b804c7460f4e14cd0aa393d129 (patch)
treed46294f35150c4f0f43deaf2d31fceaf945ae715 /3rdParty/Boost/boost/thread/pthread/once.hpp
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Import.
Diffstat (limited to '3rdParty/Boost/boost/thread/pthread/once.hpp')
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diff --git a/3rdParty/Boost/boost/thread/pthread/once.hpp b/3rdParty/Boost/boost/thread/pthread/once.hpp
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+#ifndef BOOST_THREAD_PTHREAD_ONCE_HPP
+#define BOOST_THREAD_PTHREAD_ONCE_HPP
+
+// once.hpp
+//
+// (C) Copyright 2007-8 Anthony Williams
+//
+// 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)
+
+#include <boost/thread/detail/config.hpp>
+
+#include <pthread.h>
+#include <boost/assert.hpp>
+#include "pthread_mutex_scoped_lock.hpp"
+#include <boost/thread/pthread/pthread_mutex_scoped_lock.hpp>
+#include <boost/cstdint.hpp>
+
+#include <boost/config/abi_prefix.hpp>
+
+namespace boost
+{
+
+ struct once_flag
+ {
+ boost::uintmax_t epoch;
+ };
+
+ namespace detail
+ {
+ BOOST_THREAD_DECL boost::uintmax_t& get_once_per_thread_epoch();
+ BOOST_THREAD_DECL extern boost::uintmax_t once_global_epoch;
+ BOOST_THREAD_DECL extern pthread_mutex_t once_epoch_mutex;
+ BOOST_THREAD_DECL extern pthread_cond_t once_epoch_cv;
+ }
+
+#define BOOST_ONCE_INITIAL_FLAG_VALUE 0
+#define BOOST_ONCE_INIT {BOOST_ONCE_INITIAL_FLAG_VALUE}
+
+
+ // Based on Mike Burrows fast_pthread_once algorithm as described in
+ // http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2007/n2444.html
+ template<typename Function>
+ void call_once(once_flag& flag,Function f)
+ {
+ static boost::uintmax_t const uninitialized_flag=BOOST_ONCE_INITIAL_FLAG_VALUE;
+ static boost::uintmax_t const being_initialized=uninitialized_flag+1;
+ boost::uintmax_t const epoch=flag.epoch;
+ boost::uintmax_t& this_thread_epoch=detail::get_once_per_thread_epoch();
+
+ if(epoch<this_thread_epoch)
+ {
+ pthread::pthread_mutex_scoped_lock lk(&detail::once_epoch_mutex);
+
+ while(flag.epoch<=being_initialized)
+ {
+ if(flag.epoch==uninitialized_flag)
+ {
+ flag.epoch=being_initialized;
+ try
+ {
+ pthread::pthread_mutex_scoped_unlock relocker(&detail::once_epoch_mutex);
+ f();
+ }
+ catch(...)
+ {
+ flag.epoch=uninitialized_flag;
+ BOOST_VERIFY(!pthread_cond_broadcast(&detail::once_epoch_cv));
+ throw;
+ }
+ flag.epoch=--detail::once_global_epoch;
+ BOOST_VERIFY(!pthread_cond_broadcast(&detail::once_epoch_cv));
+ }
+ else
+ {
+ while(flag.epoch==being_initialized)
+ {
+ BOOST_VERIFY(!pthread_cond_wait(&detail::once_epoch_cv,&detail::once_epoch_mutex));
+ }
+ }
+ }
+ this_thread_epoch=detail::once_global_epoch;
+ }
+ }
+}
+
+#include <boost/config/abi_suffix.hpp>
+
+#endif