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