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386 lines
11 KiB
386 lines
11 KiB
/* /////////////////////////////////////////////////////////////////////////
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* File: unixstl/synch/semaphore.hpp
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*
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* Purpose: Semaphore class, based on POSIX semaphore object.
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*
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* Created: 30th May 2006
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* Updated: 10th August 2009
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*
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* Home: http://stlsoft.org/
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*
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* Copyright (c) 2006-2009, 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/semaphore.hpp
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*
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* \brief [C++ only] Definition of unixstl::semaphore 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_SEMAPHORE
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#define UNIXSTL_INCL_UNIXSTL_SYNCH_HPP_SEMAPHORE
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#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
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# define UNIXSTL_VER_UNIXSTL_SYNCH_HPP_SEMAPHORE_MAJOR 1
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# define UNIXSTL_VER_UNIXSTL_SYNCH_HPP_SEMAPHORE_MINOR 2
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# define UNIXSTL_VER_UNIXSTL_SYNCH_HPP_SEMAPHORE_REVISION 2
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# define UNIXSTL_VER_UNIXSTL_SYNCH_HPP_SEMAPHORE_EDIT 20
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#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */
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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 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 UNIXSTL_INCL_UNIXSTL_SYNCH_ERROR_HPP_EXCEPTIONS
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# include <unixstl/synch/error/exceptions.hpp>
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#endif /* !UNIXSTL_INCL_UNIXSTL_SYNCH_ERROR_HPP_EXCEPTIONS */
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#ifndef STLSOFT_INCL_H_ERRNO
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# define STLSOFT_INCL_H_ERRNO
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# include <errno.h>
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#endif /* !STLSOFT_INCL_H_ERRNO */
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#ifndef STLSOFT_INCL_H_SEMAPHORE
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# define STLSOFT_INCL_H_SEMAPHORE
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# include <semaphore.h>
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#endif /* !STLSOFT_INCL_H_SEMAPHORE */
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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 semaphore
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/** \brief This class acts as an semaphore based on the POSIX
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* semaphore object
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*
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* \ingroup group__library__synch
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*/
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class semaphore
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: public stlsoft_ns_qual(critical_section)< STLSOFT_CRITICAL_SECTION_ISNOT_RECURSIVE
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, STLSOFT_CRITICAL_SECTION_IS_TRYABLE
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>
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, public stlsoft_ns_qual(synchronisable_object_tag)
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{
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/// \name Member Types
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/// @{
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public:
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typedef semaphore class_type;
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typedef sem_t* handle_type;
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typedef us_bool_t bool_type;
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typedef us_size_t count_type;
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typedef sem_t* resource_type;
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/// @}
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/// \name Member Constants
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/// @{
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public:
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enum
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{
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maxCountValue = _POSIX_SEM_VALUE_MAX // Borrowed from PThreads-win32
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};
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/// @}
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/// \name Construction
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/// @{
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public:
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/// \brief Conversion constructor
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semaphore(handle_type sem, bool_type bTakeOwnership)
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: m_sem(sem)
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, m_bOwnHandle(bTakeOwnership)
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{
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UNIXSTL_ASSERT(NULL != sem);
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}
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/// \brief Creates an instance of the semaphore
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ss_explicit_k semaphore(count_type initialCount, bool_type bInterProcessShared = false)
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: m_sem(create_semaphore_(&m_semInternal, initialCount, bInterProcessShared))
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, m_bOwnHandle(true)
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{}
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/// \brief Destroys an instance of the semaphore
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~semaphore() stlsoft_throw_0()
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{
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if( NULL != m_sem &&
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m_bOwnHandle)
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{
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::sem_destroy(m_sem);
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}
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}
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#if 0
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void close() stlsoft_throw_0()
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{
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if( NULL != m_sem &&
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m_bOwnHandle)
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{
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::sem_destroy(m_sem);
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m_sem = NULL;
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}
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}
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#endif /* 0 */
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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 semaphore, pending the thread until the lock is aquired
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void lock()
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{
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UNIXSTL_ASSERT(NULL != m_sem);
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if(::sem_wait(m_sem) < 0)
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{
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#ifdef STLSOFT_CF_EXCEPTION_SUPPORT
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STLSOFT_THROW_X(synchronisation_exception("semaphore wait failed", errno));
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#endif /* STLSOFT_CF_EXCEPTION_SUPPORT */
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}
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}
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/// \brief Attempts to lock the semaphore
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///
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/// \return <b>true</b> if the semaphore was aquired, or <b>false</b> if not
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bool_type try_lock()
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{
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UNIXSTL_ASSERT(NULL != m_sem);
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int res = ::sem_trywait(m_sem);
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if(0 == res)
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{
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return true;
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}
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else
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{
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if(EAGAIN != res)
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{
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#ifdef STLSOFT_CF_EXCEPTION_SUPPORT
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STLSOFT_THROW_X(synchronisation_exception("semaphore wait failed", errno));
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#endif /* STLSOFT_CF_EXCEPTION_SUPPORT */
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}
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}
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return false;
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}
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/// \brief Releases an aquired lock on the semaphore, increasing the
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/// semaphore's counter by one.
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void unlock()
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{
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UNIXSTL_ASSERT(NULL != m_sem);
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if(::sem_post(m_sem) < 0)
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{
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#ifdef STLSOFT_CF_EXCEPTION_SUPPORT
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STLSOFT_THROW_X(synchronisation_exception("semaphore release failed", errno));
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#endif /* STLSOFT_CF_EXCEPTION_SUPPORT */
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}
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}
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/// @}
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/// \name Accessors
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/// @{
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public:
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/// \brief The underlying kernel object handle
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handle_type handle() stlsoft_throw_0()
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{
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return m_sem;
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}
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/// \brief The underlying kernel object handle
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handle_type get() stlsoft_throw_0()
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{
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return m_sem;
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}
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/// @}
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// Implementation
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private:
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static handle_type create_semaphore_(sem_t* internal, count_type initialCount, bool_type bInterProcessShared)
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{
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UNIXSTL_ASSERT(initialCount <= maxCountValue);
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handle_type sem;
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if(::sem_init(internal, bInterProcessShared, initialCount) < 0)
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{
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#ifdef STLSOFT_CF_EXCEPTION_SUPPORT
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STLSOFT_THROW_X(synchronisation_exception("Failed to create kernel semaphore object", errno));
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#else /* ? STLSOFT_CF_EXCEPTION_SUPPORT */
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sem = NULL;
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#endif /* STLSOFT_CF_EXCEPTION_SUPPORT */
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}
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else
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{
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sem = internal;
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}
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return sem;
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}
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// Members
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private:
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sem_t m_semInternal; // The actual object if internally initialised
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handle_type m_sem; // Handle to the underlying semaphore object
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const bool_type m_bOwnHandle; // Does the instance own the handle?
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// Not to be implemented
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private:
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semaphore(class_type const& rhs);
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semaphore& operator =(class_type const& rhs);
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};
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/* /////////////////////////////////////////////////////////////////////////
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* 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 semaphore
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*
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* \ingroup group__concept__shim__synchronisation_control
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*
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* \param sem The semaphore on which to aquire the lock.
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*/
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inline void lock_instance(unixstl_ns_qual(semaphore) &sem)
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{
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sem.lock();
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}
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/** \brief This \ref group__concept__shims "control shim" releases a lock on the given semaphore
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*
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* \ingroup group__concept__shim__synchronisation_control
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*
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* \param sem The semaphore on which to release the lock
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*/
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inline void unlock_instance(unixstl_ns_qual(semaphore) &sem)
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{
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sem.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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# else
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namespace unixstl_project {
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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 semaphore class
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*
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* \ingroup group__library__synch
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*/
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struct semaphore_lock_traits
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{
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public:
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/// The lockable type
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typedef semaphore lock_type;
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typedef semaphore_lock_traits class_type;
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// Operations
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public:
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/// Lock the given semaphore instance
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static void lock(semaphore &c)
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{
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lock_instance(c);
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}
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/// Unlock the given semaphore instance
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static void unlock(semaphore &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/semaphore_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_SEMAPHORE */
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/* ///////////////////////////// end of file //////////////////////////// */
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