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427 lines
14 KiB
427 lines
14 KiB
/* /////////////////////////////////////////////////////////////////////////
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* File: unixstl/synch/spin_mutex.hpp (originally MWSpinMx.h, ::SynesisWin)
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*
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* Purpose: Intra-process mutex, based on spin waits.
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*
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* Created: 27th August 1997
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* Updated: 10th August 2009
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*
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* Thanks: To Rupert Kittinger, for pointing out that the prior
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* implementation that always yielded was not really "spinning".
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*
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* Brad Cox, for helping out in testing and fixing the
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* implementation for MAC OSX (Intel).
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*
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* Home: http://stlsoft.org/
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*
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* Copyright (c) 1997-2009, Matthew Wilson and Synesis Software
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* - Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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* - Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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* - Neither the name(s) of Matthew Wilson and Synesis Software nor the names of
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* any contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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* ////////////////////////////////////////////////////////////////////// */
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/** \file unixstl/synch/spin_mutex.hpp
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*
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* \brief [C++ only] Definition of the unixstl::spin_mutex class
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* (\ref group__library__synch "Synchronisation" Library).
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*/
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#ifndef UNIXSTL_INCL_UNIXSTL_SYNCH_HPP_SPIN_MUTEX
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#define UNIXSTL_INCL_UNIXSTL_SYNCH_HPP_SPIN_MUTEX
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#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
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# define UNIXSTL_VER_UNIXSTL_SYNCH_HPP_SPIN_MUTEX_MAJOR 5
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# define UNIXSTL_VER_UNIXSTL_SYNCH_HPP_SPIN_MUTEX_MINOR 0
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# define UNIXSTL_VER_UNIXSTL_SYNCH_HPP_SPIN_MUTEX_REVISION 3
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# define UNIXSTL_VER_UNIXSTL_SYNCH_HPP_SPIN_MUTEX_EDIT 60
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#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
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/* /////////////////////////////////////////////////////////////////////////
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* Auto-generation and compatibility
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*/
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/*
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[Incompatibilies-start]
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!UNIXSTL_OS_IS_MACOSX:
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[Incompatibilies-end]
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*/
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/* /////////////////////////////////////////////////////////////////////////
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* Includes
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*/
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#ifndef UNIXSTL_INCL_UNIXSTL_H_UNIXSTL
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# include <unixstl/unixstl.h>
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#endif /* !UNIXSTL_INCL_UNIXSTL_H_UNIXSTL */
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#ifndef UNIXSTL_INCL_UNIXSTL_SYNCH_UTIL_H_FEATURES
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# include <unixstl/synch/util/features.h>
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#endif /* !UNIXSTL_INCL_UNIXSTL_SYNCH_UTIL_H_FEATURES */
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#ifndef UNIXSTL_HAS_ATOMIC_INTEGER_OPERATIONS
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# error unixstl/synch/spin_mutex.hpp requires support for atomic integer operations. Consult unixstl/synch/util/features.h for details
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#endif /* !UNIXSTL_HAS_ATOMIC_INTEGER_OPERATIONS */
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#ifndef UNIXSTL_INCL_UNIXSTL_SYNCH_H_ATOMIC_FUNCTIONS
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# include <unixstl/synch/atomic_functions.h>
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#endif /* !UNIXSTL_INCL_UNIXSTL_SYNCH_H_ATOMIC_FUNCTIONS */
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#ifndef STLSOFT_INCL_STLSOFT_SYNCH_HPP_CONCEPTS
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# include <stlsoft/synch/concepts.hpp>
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#endif /* !STLSOFT_INCL_STLSOFT_SYNCH_HPP_CONCEPTS */
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#ifndef STLSOFT_INCL_STLSOFT_SYNCH_HPP_SPIN_POLICIES
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# include <stlsoft/synch/spin_policies.hpp>
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#endif /* !STLSOFT_INCL_STLSOFT_SYNCH_HPP_SPIN_POLICIES */
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#ifndef STLSOFT_INCL_H_SCHED
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# define STLSOFT_INCL_H_SCHED
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# include <sched.h>
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#endif /* !STLSOFT_INCL_H_SCHED */
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#ifdef STLSOFT_UNITTEST
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# include <stlsoft/synch/lock_scope.hpp>
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#endif /* STLSOFT_UNITTEST */
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#if defined(_DEBUG)
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# define STLSOFT_SPINMUTEX_COUNT_LOCKS
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#endif /* _DEBUG */
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/* /////////////////////////////////////////////////////////////////////////
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* Namespace
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*/
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#ifndef _UNIXSTL_NO_NAMESPACE
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# if defined(_STLSOFT_NO_NAMESPACE) || \
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defined(STLSOFT_DOCUMENTATION_SKIP_SECTION)
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/* There is no stlsoft namespace, so must define ::unixstl */
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namespace unixstl
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{
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# else
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/* Define stlsoft::unixstl_project */
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namespace stlsoft
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{
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namespace unixstl_project
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{
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# endif /* _STLSOFT_NO_NAMESPACE */
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#endif /* !_UNIXSTL_NO_NAMESPACE */
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/* /////////////////////////////////////////////////////////////////////////
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* Classes
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*/
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// class spin_mutex
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/** \brief This class provides an implementation of the mutex model based on
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* a spinning mechanism.
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*
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* \ingroup group__library__synch
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*
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* \note A spin mutex is not recursive. If you re-enter it your thread will
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* be in irrecoverable deadlock.
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*/
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template <ss_typename_param_k SP>
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class spin_mutex_base
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: public stlsoft_ns_qual(critical_section)< STLSOFT_CRITICAL_SECTION_ISNOT_RECURSIVE
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, STLSOFT_CRITICAL_SECTION_ISNOT_TRYABLE
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>
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{
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/// \name Member Types
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/// @{
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private:
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/// \brief The spin-policy class
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typedef SP spin_policy_class;
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public:
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/// \brief This class
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typedef spin_mutex_base<SP> class_type;
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/// \brief The atomic integer type
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typedef unixstl_ns_qual(atomic_int_t) atomic_int_type;
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/// \brief The count type
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typedef us_sint32_t count_type;
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/// \brief The bool type
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typedef us_bool_t bool_type;
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/// @}
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/// \name Construction
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/// @{
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public:
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#ifdef __SYNSOFT_DBS_COMPILER_SUPPORTS_PRAGMA_MESSAGE
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# pragma message(_sscomp_fileline_message("Create stlsoft/synch/spin_mutex_base.hpp, and factor out"))
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#endif /* __SYNSOFT_DBS_COMPILER_SUPPORTS_PRAGMA_MESSAGE */
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/// \brief Creates an instance of the mutex
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///
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/// \param p Pointer to an external counter variable. May be NULL, in
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/// which case an internal member is used for the counter variable.
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///
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/// \note
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ss_explicit_k spin_mutex_base(atomic_int_type *p = NULL) stlsoft_throw_0()
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: m_spinCount((NULL != p) ? p : &m_internalCount)
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, m_internalCount(0)
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#ifdef STLSOFT_SPINMUTEX_COUNT_LOCKS
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, m_cLocks(0)
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#endif // STLSOFT_SPINMUTEX_COUNT_LOCKS
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, m_spunCount(0)
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, m_bYieldOnSpin(spin_policy_class::value)
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{}
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/// \brief Creates an instance of the mutex
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///
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/// \param p Pointer to an external counter variable. May be NULL, in
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/// which case an internal member is used for the counter variable.
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/// \param bYieldOnSpin
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spin_mutex_base(atomic_int_type *p, bool_type bYieldOnSpin) stlsoft_throw_0()
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: m_spinCount((NULL != p) ? p : &m_internalCount)
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, m_internalCount(0)
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#ifdef STLSOFT_SPINMUTEX_COUNT_LOCKS
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, m_cLocks(0)
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#endif // STLSOFT_SPINMUTEX_COUNT_LOCKS
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, m_spunCount(0)
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, m_bYieldOnSpin(bYieldOnSpin)
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{}
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/// Destroys an instance of the mutex
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~spin_mutex_base() stlsoft_throw_0()
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{
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#ifdef STLSOFT_SPINMUTEX_COUNT_LOCKS
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UNIXSTL_ASSERT(0 == m_cLocks);
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#endif // STLSOFT_SPINMUTEX_COUNT_LOCKS
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}
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/// @}
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/// \name Operations
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/// @{
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public:
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/// \brief Acquires a lock on the mutex, pending the thread until the lock is aquired
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void lock() stlsoft_throw_0()
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{
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#ifdef UNIXSTL_SPINMUTEX_CHECK_INIT
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// If the dynamic initialisation phase has been skipped, the
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// members will all be assigned to 0, which is correct for
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// all except m_spinCount, which must be assigned to
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// &m_internalCount
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if(NULL == m_spinCount)
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{
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m_spinCount = &m_internalCount;
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}
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#endif /* UNIXSTL_SPINMUTEX_CHECK_INIT */
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UNIXSTL_MESSAGE_ASSERT("A global instance of spin_mutex has skipped dynamic initialisation. You must #define UNIXSTL_SPINMUTEX_CHECK_INIT if your compilation causes dynamic initialisation to be skipped.", NULL != m_spinCount);
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#if defined(UNIXSTL_OS_IS_LINUX) && \
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!defined(UNIXSTL_ARCH_IS_INTEL)
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for(m_spunCount = 1; 0 != ::atomic_inc_and_test(m_spinCount); ++m_spunCount)
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#elif defined(UNIXSTL_OS_IS_MACOSX)
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for(m_spunCount = 1; !::OSAtomicCompareAndSwap32Barrier(0, 1, m_spinCount); ++m_spunCount)
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#elif defined(UNIXSTL_HAS_ATOMIC_WRITE)
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for(m_spunCount = 1; 0 != atomic_write(m_spinCount, 1); ++m_spunCount)
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#else /* ? arch */
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# error Your platform does not support atomic_write(), or has provides it in a manner unknown to the authors of UNIXSTL. If you know of the correct implementation, please send a patch.
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#endif /* arch */
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{
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if(m_bYieldOnSpin)
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{
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::sched_yield();
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}
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}
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#ifdef STLSOFT_SPINMUTEX_COUNT_LOCKS
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UNIXSTL_ASSERT(0 != ++m_cLocks);
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#endif // STLSOFT_SPINMUTEX_COUNT_LOCKS
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}
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/// \brief Releases an aquired lock on the mutex
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void unlock() stlsoft_throw_0()
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{
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#ifdef STLSOFT_SPINMUTEX_COUNT_LOCKS
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UNIXSTL_ASSERT(m_cLocks-- != 0);
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#endif // STLSOFT_SPINMUTEX_COUNT_LOCKS
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m_spunCount = 0;
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#if defined(UNIXSTL_OS_IS_LINUX) && \
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!defined(UNIXSTL_ARCH_IS_INTEL)
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::atomic_dec(m_spinCount);
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#elif defined(UNIXSTL_OS_IS_MACOSX)
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::OSAtomicDecrement32Barrier(m_spinCount);
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#else /* ? arch */
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atomic_write(m_spinCount, 0);
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#endif /* arch */
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}
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/// @}
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/// \name Attributes
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/// @{
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public:
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/// \brief An indicator as to the level of contention on the mutex.
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///
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/// \note The value returned is only meaningful after lock() has been
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/// called and before a corresponding unlock() has been called.
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///
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/// \note The value returned is only reliable when an external counter
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/// variable is being used, and when each spin_mutex instance is
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/// thread-specific. In all other cases, the spun count is subject to
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/// race conditions (that do <b>not</b> affect the good functioning of
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/// the spin_mutex) and value returned may be, at best, used only as a
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/// guide as to contention.
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count_type spun_count() const
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{
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return m_spunCount;
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}
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/// @}
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/// \name Members
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/// @{
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private:
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atomic_int_type *m_spinCount;
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atomic_int_type m_internalCount;
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#ifdef STLSOFT_SPINMUTEX_COUNT_LOCKS
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count_type m_cLocks; // Used as check on matched Lock/Unlock calls
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#endif // STLSOFT_SPINMUTEX_COUNT_LOCKS
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count_type m_spunCount;
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const bool_type m_bYieldOnSpin;
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/// @}
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/// \name Not to be implemented
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/// @{
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private:
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spin_mutex_base(class_type const& rhs);
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class_type& operator =(class_type const& rhs);
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/// @}
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};
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typedef spin_mutex_base<stlsoft_ns_qual(spin_yield)> spin_mutex_yield;
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typedef spin_mutex_base<stlsoft_ns_qual(spin_no_yield)> spin_mutex_no_yield;
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#ifdef STLSOFT_OLD_SPIN_MUTEX_BEHAVIOUR
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typedef spin_mutex_no_yield spin_mutex;
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#else /* ? STLSOFT_OLD_SPIN_MUTEX_BEHAVIOUR */
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typedef spin_mutex_yield spin_mutex;
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#endif /* STLSOFT_OLD_SPIN_MUTEX_BEHAVIOUR */
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/* /////////////////////////////////////////////////////////////////////////
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* Control shims
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*/
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#ifndef _UNIXSTL_NO_NAMESPACE
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# if defined(_STLSOFT_NO_NAMESPACE) || \
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defined(STLSOFT_DOCUMENTATION_SKIP_SECTION)
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} // namespace unixstl
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# else
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} // namespace unixstl_project
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# endif /* _STLSOFT_NO_NAMESPACE */
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#endif /* !_UNIXSTL_NO_NAMESPACE */
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/** \brief This \ref group__concept__shims "control shim" aquires a lock on the given mutex
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*
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* \ingroup group__concept__shim__synchronisation_control
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*
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* \param mx The mutex on which to aquire the lock.
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*/
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template <ss_typename_param_k SP>
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inline void lock_instance(unixstl_ns_qual(spin_mutex_base)<SP> &mx)
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{
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mx.lock();
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}
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/** \brief This \ref group__concept__shims "control shim" releases a lock on the given mutex
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*
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* \ingroup group__concept__shim__synchronisation_control
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*
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* \param mx The mutex on which to release the lock
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*/
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template <ss_typename_param_k SP>
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inline void unlock_instance(unixstl_ns_qual(spin_mutex_base)<SP> &mx)
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{
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mx.unlock();
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}
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#ifndef _UNIXSTL_NO_NAMESPACE
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# if defined(_STLSOFT_NO_NAMESPACE) || \
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defined(STLSOFT_DOCUMENTATION_SKIP_SECTION)
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namespace unixstl
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{
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# else
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namespace unixstl_project
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{
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# if defined(STLSOFT_COMPILER_IS_BORLAND)
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using ::stlsoft::lock_instance;
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using ::stlsoft::unlock_instance;
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# endif /* compiler */
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# endif /* _STLSOFT_NO_NAMESPACE */
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#endif /* !_UNIXSTL_NO_NAMESPACE */
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/* /////////////////////////////////////////////////////////////////////////
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* lock_traits
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*/
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// class lock_traits
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/** \brief Traits for the spin_mutex class
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*
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* \ingroup group__library__synch
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*/
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struct spin_mutex_lock_traits
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{
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public:
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/// The lockable type
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typedef spin_mutex lock_type;
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typedef spin_mutex_lock_traits class_type;
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// Operations
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public:
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/// Lock the given spin_mutex instance
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static void lock(spin_mutex &c)
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{
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lock_instance(c);
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}
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/// Unlock the given spin_mutex instance
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static void unlock(spin_mutex &c)
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{
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unlock_instance(c);
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}
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};
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////////////////////////////////////////////////////////////////////////////
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// Unit-testing
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#ifdef STLSOFT_UNITTEST
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# include "./unittest/spin_mutex_unittest_.h"
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#endif /* STLSOFT_UNITTEST */
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/* ////////////////////////////////////////////////////////////////////// */
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#ifndef _UNIXSTL_NO_NAMESPACE
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# if defined(_STLSOFT_NO_NAMESPACE) || \
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defined(STLSOFT_DOCUMENTATION_SKIP_SECTION)
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} // namespace unixstl
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# else
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} // namespace unixstl_project
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} // namespace stlsoft
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# endif /* _STLSOFT_NO_NAMESPACE */
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#endif /* !_UNIXSTL_NO_NAMESPACE */
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/* ////////////////////////////////////////////////////////////////////// */
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#endif /* !UNIXSTL_INCL_UNIXSTL_SYNCH_HPP_SPIN_MUTEX */
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/* ///////////////////////////// end of file //////////////////////////// */
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