Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: //
Chris@16: // (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost
Chris@16: // Software License, Version 1.0. (See accompanying file
Chris@16: // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: // See http://www.boost.org/libs/interprocess for documentation.
Chris@16: //
Chris@16: //////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: #ifndef BOOST_INTERPROCESS_SEMAPHORE_HPP
Chris@16: #define BOOST_INTERPROCESS_SEMAPHORE_HPP
Chris@16: 
Chris@101: #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16: 
Chris@101: #ifndef BOOST_CONFIG_HPP
Chris@101: #  include <boost/config.hpp>
Chris@101: #endif
Chris@101: #
Chris@101: #if defined(BOOST_HAS_PRAGMA_ONCE)
Chris@16: #  pragma once
Chris@16: #endif
Chris@16: 
Chris@16: #include <boost/interprocess/detail/config_begin.hpp>
Chris@16: #include <boost/interprocess/detail/workaround.hpp>
Chris@16: 
Chris@16: #include <boost/interprocess/creation_tags.hpp>
Chris@16: #include <boost/interprocess/exceptions.hpp>
Chris@16: #include <boost/interprocess/detail/posix_time_types_wrk.hpp>
Chris@16: 
Chris@16: #if !defined(BOOST_INTERPROCESS_FORCE_GENERIC_EMULATION) && \
Chris@101:    (defined(BOOST_INTERPROCESS_POSIX_PROCESS_SHARED) && defined(BOOST_INTERPROCESS_POSIX_UNNAMED_SEMAPHORES))
Chris@16:    #include <boost/interprocess/sync/posix/semaphore.hpp>
Chris@16:    #define BOOST_INTERPROCESS_USE_POSIX
Chris@16: //Experimental...
Chris@16: #elif !defined(BOOST_INTERPROCESS_FORCE_GENERIC_EMULATION) && defined (BOOST_INTERPROCESS_WINDOWS)
Chris@16:    #include <boost/interprocess/sync/windows/semaphore.hpp>
Chris@16:    #define BOOST_INTERPROCESS_USE_WINDOWS
Chris@16: #elif !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16:    #include <boost/interprocess/sync/spin/semaphore.hpp>
Chris@16:    #define BOOST_INTERPROCESS_USE_GENERIC_EMULATION
Chris@16: #endif
Chris@16: 
Chris@101: #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16: 
Chris@16: //!\file
Chris@16: //!Describes a interprocess_semaphore class for inter-process synchronization
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace interprocess {
Chris@16: 
Chris@16: //!Wraps a interprocess_semaphore that can be placed in shared memory and can be
Chris@16: //!shared between processes. Allows timed lock tries
Chris@16: class interprocess_semaphore
Chris@16: {
Chris@101:    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16:    //Non-copyable
Chris@16:    interprocess_semaphore(const interprocess_semaphore &);
Chris@16:    interprocess_semaphore &operator=(const interprocess_semaphore &);
Chris@101:    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16:    public:
Chris@16:    //!Creates a interprocess_semaphore with the given initial count.
Chris@16:    //!interprocess_exception if there is an error.*/
Chris@16:    interprocess_semaphore(unsigned int initialCount);
Chris@16: 
Chris@16:    //!Destroys the interprocess_semaphore.
Chris@16:    //!Does not throw
Chris@16:    ~interprocess_semaphore();
Chris@16: 
Chris@16:    //!Increments the interprocess_semaphore count. If there are processes/threads blocked waiting
Chris@16:    //!for the interprocess_semaphore, then one of these processes will return successfully from
Chris@16:    //!its wait function. If there is an error an interprocess_exception exception is thrown.
Chris@16:    void post();
Chris@16: 
Chris@16:    //!Decrements the interprocess_semaphore. If the interprocess_semaphore value is not greater than zero,
Chris@16:    //!then the calling process/thread blocks until it can decrement the counter.
Chris@16:    //!If there is an error an interprocess_exception exception is thrown.
Chris@16:    void wait();
Chris@16: 
Chris@16:    //!Decrements the interprocess_semaphore if the interprocess_semaphore's value is greater than zero
Chris@16:    //!and returns true. If the value is not greater than zero returns false.
Chris@16:    //!If there is an error an interprocess_exception exception is thrown.
Chris@16:    bool try_wait();
Chris@16: 
Chris@16:    //!Decrements the interprocess_semaphore if the interprocess_semaphore's value is greater
Chris@16:    //!than zero and returns true. Otherwise, waits for the interprocess_semaphore
Chris@16:    //!to the posted or the timeout expires. If the timeout expires, the
Chris@16:    //!function returns false. If the interprocess_semaphore is posted the function
Chris@16:    //!returns true. If there is an error throws sem_exception
Chris@16:    bool timed_wait(const boost::posix_time::ptime &abs_time);
Chris@16: 
Chris@16:    //!Returns the interprocess_semaphore count
Chris@16: //   int get_count() const;
Chris@101:    #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED)
Chris@16:    private:
Chris@16:    #if defined(BOOST_INTERPROCESS_USE_GENERIC_EMULATION)
Chris@16:       #undef BOOST_INTERPROCESS_USE_GENERIC_EMULATION
Chris@16:       ipcdetail::spin_semaphore m_sem;
Chris@16:    #elif defined(BOOST_INTERPROCESS_USE_WINDOWS)
Chris@16:       #undef BOOST_INTERPROCESS_USE_WINDOWS
Chris@16:       ipcdetail::windows_semaphore m_sem;
Chris@16:    #else
Chris@16:       #undef BOOST_INTERPROCESS_USE_POSIX
Chris@16:       ipcdetail::posix_semaphore m_sem;
Chris@16:    #endif   //#if defined(BOOST_INTERPROCESS_USE_GENERIC_EMULATION)
Chris@101:    #endif   //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED
Chris@16: };
Chris@16: 
Chris@16: }  //namespace interprocess {
Chris@16: }  //namespace boost {
Chris@16: 
Chris@16: namespace boost {
Chris@16: namespace interprocess {
Chris@16: 
Chris@16: inline interprocess_semaphore::interprocess_semaphore(unsigned int initialCount)
Chris@16:    : m_sem(initialCount)
Chris@16: {}
Chris@16: 
Chris@16: inline interprocess_semaphore::~interprocess_semaphore(){}
Chris@16: 
Chris@16: inline void interprocess_semaphore::wait()
Chris@16: {
Chris@16:    #ifdef BOOST_INTERPROCESS_ENABLE_TIMEOUT_WHEN_LOCKING
Chris@16:       boost::posix_time::ptime wait_time
Chris@16:          = boost::posix_time::microsec_clock::universal_time()
Chris@16:          + boost::posix_time::milliseconds(BOOST_INTERPROCESS_TIMEOUT_WHEN_LOCKING_DURATION_MS);
Chris@16:       if (!m_sem.timed_wait(wait_time))
Chris@16:       {
Chris@16:          throw interprocess_exception(timeout_when_waiting_error, "Interprocess semaphore timeout when waiting. Possible deadlock: owner died without posting?");
Chris@16:       }
Chris@16:    #else
Chris@16:       m_sem.wait();
Chris@16:    #endif
Chris@16: }
Chris@16: inline bool interprocess_semaphore::try_wait()
Chris@16: { return m_sem.try_wait(); }
Chris@16: 
Chris@16: inline bool interprocess_semaphore::timed_wait(const boost::posix_time::ptime &abs_time)
Chris@16: { return m_sem.timed_wait(abs_time); }
Chris@16: 
Chris@16: inline void interprocess_semaphore::post()
Chris@16: { m_sem.post(); }
Chris@16: 
Chris@16: }  //namespace interprocess {
Chris@16: }  //namespace boost {
Chris@16: 
Chris@16: #include <boost/interprocess/detail/config_end.hpp>
Chris@16: 
Chris@16: #endif   //BOOST_INTERPROCESS_SEMAPHORE_HPP