//////////////////////////////////////////////////////////////////////////////
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//
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// (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
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// Software License, Version 1.0. (See accompanying file
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// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
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//
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// See http://www.boost.org/libs/interprocess for documentation.
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//
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//////////////////////////////////////////////////////////////////////////////
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#ifndef BOOST_INTERPROCESS_SEMAPHORE_HPP
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#define BOOST_INTERPROCESS_SEMAPHORE_HPP
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#if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
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#ifndef BOOST_CONFIG_HPP
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# include <boost/config.hpp>
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#endif
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#
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#if defined(BOOST_HAS_PRAGMA_ONCE)
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# pragma once
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#endif
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#include <boost/interprocess/detail/config_begin.hpp>
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#include <boost/interprocess/detail/workaround.hpp>
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#include <boost/interprocess/creation_tags.hpp>
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#include <boost/interprocess/exceptions.hpp>
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#include <boost/interprocess/detail/posix_time_types_wrk.hpp>
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#include <boost/interprocess/sync/detail/locks.hpp>
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#include <boost/interprocess/sync/detail/common_algorithms.hpp>
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#if !defined(BOOST_INTERPROCESS_FORCE_GENERIC_EMULATION) && \
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(defined(BOOST_INTERPROCESS_POSIX_PROCESS_SHARED) && defined(BOOST_INTERPROCESS_POSIX_UNNAMED_SEMAPHORES))
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#include <boost/interprocess/sync/posix/semaphore.hpp>
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#define BOOST_INTERPROCESS_USE_POSIX
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//Experimental...
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#elif !defined(BOOST_INTERPROCESS_FORCE_GENERIC_EMULATION) && defined (BOOST_INTERPROCESS_WINDOWS)
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#include <boost/interprocess/sync/windows/semaphore.hpp>
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#define BOOST_INTERPROCESS_USE_WINDOWS
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#elif !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
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#include <boost/interprocess/sync/spin/semaphore.hpp>
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#define BOOST_INTERPROCESS_USE_GENERIC_EMULATION
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#endif
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#endif //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
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//!\file
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//!Describes a interprocess_semaphore class for inter-process synchronization
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namespace boost {
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namespace interprocess {
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//!Wraps a interprocess_semaphore that can be placed in shared memory and can be
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//!shared between processes. Allows timed lock tries
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class interprocess_semaphore
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{
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#if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
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//Non-copyable
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interprocess_semaphore(const interprocess_semaphore &);
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interprocess_semaphore &operator=(const interprocess_semaphore &);
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#endif //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
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public:
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//!Creates a interprocess_semaphore with the given initial count.
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//!interprocess_exception if there is an error.*/
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interprocess_semaphore(unsigned int initialCount);
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//!Destroys the interprocess_semaphore.
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//!Does not throw
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~interprocess_semaphore();
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//!Increments the interprocess_semaphore count. If there are processes/threads blocked waiting
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//!for the interprocess_semaphore, then one of these processes will return successfully from
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//!its wait function. If there is an error an interprocess_exception exception is thrown.
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void post();
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//!Decrements the interprocess_semaphore. If the interprocess_semaphore value is not greater than zero,
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//!then the calling process/thread blocks until it can decrement the counter.
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//!If there is an error an interprocess_exception exception is thrown.
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void wait();
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//!Decrements the interprocess_semaphore if the interprocess_semaphore's value is greater than zero
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//!and returns true. If the value is not greater than zero returns false.
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//!If there is an error an interprocess_exception exception is thrown.
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bool try_wait();
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//!Decrements the interprocess_semaphore if the interprocess_semaphore's value is greater
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//!than zero and returns true. Otherwise, waits for the interprocess_semaphore
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//!to the posted or the timeout expires. If the timeout expires, the
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//!function returns false. If the interprocess_semaphore is posted the function
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//!returns true. If there is an error throws sem_exception
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bool timed_wait(const boost::posix_time::ptime &abs_time);
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//!Returns the interprocess_semaphore count
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// int get_count() const;
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#if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
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private:
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#if defined(BOOST_INTERPROCESS_USE_GENERIC_EMULATION)
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#undef BOOST_INTERPROCESS_USE_GENERIC_EMULATION
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typedef ipcdetail::spin_semaphore internal_sem_t;
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#elif defined(BOOST_INTERPROCESS_USE_WINDOWS)
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#undef BOOST_INTERPROCESS_USE_WINDOWS
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typedef ipcdetail::windows_semaphore internal_sem_t;
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#else
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#undef BOOST_INTERPROCESS_USE_POSIX
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typedef ipcdetail::posix_semaphore internal_sem_t;
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#endif //#if defined(BOOST_INTERPROCESS_USE_GENERIC_EMULATION)
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internal_sem_t m_sem;
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#endif //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
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};
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} //namespace interprocess {
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} //namespace boost {
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namespace boost {
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namespace interprocess {
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inline interprocess_semaphore::interprocess_semaphore(unsigned int initialCount)
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: m_sem(initialCount)
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{}
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inline interprocess_semaphore::~interprocess_semaphore(){}
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inline void interprocess_semaphore::wait()
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{
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ipcdetail::lock_to_wait<internal_sem_t> ltw(m_sem);
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timeout_when_locking_aware_lock(ltw);
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}
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inline bool interprocess_semaphore::try_wait()
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{ return m_sem.try_wait(); }
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inline bool interprocess_semaphore::timed_wait(const boost::posix_time::ptime &abs_time)
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{ return m_sem.timed_wait(abs_time); }
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inline void interprocess_semaphore::post()
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{ m_sem.post(); }
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} //namespace interprocess {
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} //namespace boost {
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#include <boost/interprocess/detail/config_end.hpp>
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#endif //BOOST_INTERPROCESS_SEMAPHORE_HPP
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