| ////////////////////////////////////////////////////////////////////////////// |
| // |
| // (C) Copyright Ion Gaztanaga 2005-2009. 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_NAMED_SEMAPHORE_HPP |
| #define BOOST_INTERPROCESS_NAMED_SEMAPHORE_HPP |
| |
| #if (defined _MSC_VER) && (_MSC_VER >= 1200) |
| # 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/permissions.hpp> |
| #include <boost/interprocess/detail/interprocess_tester.hpp> |
| #include <boost/interprocess/detail/posix_time_types_wrk.hpp> |
| |
| #if defined(BOOST_INTERPROCESS_NAMED_SEMAPHORE_USES_POSIX_SEMAPHORES) |
| #include <boost/interprocess/sync/posix/semaphore_wrapper.hpp> |
| #else |
| #include <boost/interprocess/shared_memory_object.hpp> |
| #include <boost/interprocess/detail/managed_open_or_create_impl.hpp> |
| #include <boost/interprocess/sync/interprocess_semaphore.hpp> |
| #include <boost/interprocess/sync/emulation/named_creation_functor.hpp> |
| #endif |
| |
| //!\file |
| //!Describes a named semaphore class for inter-process synchronization |
| |
| namespace boost { |
| namespace interprocess { |
| |
| //!A semaphore with a global name, so it can be found from different |
| //!processes. Allows several resource sharing patterns and efficient |
| //!acknowledgment mechanisms. |
| class named_semaphore |
| { |
| /// @cond |
| |
| //Non-copyable |
| named_semaphore(); |
| named_semaphore(const named_semaphore &); |
| named_semaphore &operator=(const named_semaphore &); |
| /// @endcond |
| |
| public: |
| //!Creates a global semaphore with a name, and an initial count. |
| //!If the semaphore can't be created throws interprocess_exception |
| named_semaphore(create_only_t, const char *name, unsigned int initialCount, const permissions &perm = permissions()); |
| |
| //!Opens or creates a global semaphore with a name, and an initial count. |
| //!If the semaphore is created, this call is equivalent to |
| //!named_semaphore(create_only_t, ...) |
| //!If the semaphore is already created, this call is equivalent to |
| //!named_semaphore(open_only_t, ... ) |
| //!and initialCount is ignored. |
| named_semaphore(open_or_create_t, const char *name, unsigned int initialCount, const permissions &perm = permissions()); |
| |
| //!Opens a global semaphore with a name if that semaphore is previously. |
| //!created. If it is not previously created this function throws |
| //!interprocess_exception. |
| named_semaphore(open_only_t, const char *name); |
| |
| //!Destroys *this and indicates that the calling process is finished using |
| //!the resource. The destructor function will deallocate |
| //!any system resources allocated by the system for use by this process for |
| //!this resource. The resource can still be opened again calling |
| //!the open constructor overload. To erase the resource from the system |
| //!use remove(). |
| ~named_semaphore(); |
| |
| //!Increments the semaphore count. If there are processes/threads blocked waiting |
| //!for the 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 semaphore. If the 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 semaphore if the 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 semaphore if the semaphore's value is greater |
| //!than zero and returns true. Otherwise, waits for the semaphore |
| //!to the posted or the timeout expires. If the timeout expires, the |
| //!function returns false. If the 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); |
| |
| //!Erases a named semaphore from the system. |
| //!Returns false on error. Never throws. |
| static bool remove(const char *name); |
| |
| /// @cond |
| private: |
| friend class detail::interprocess_tester; |
| void dont_close_on_destruction(); |
| |
| #if defined(BOOST_INTERPROCESS_NAMED_SEMAPHORE_USES_POSIX_SEMAPHORES) |
| detail::named_semaphore_wrapper m_sem; |
| #else |
| interprocess_semaphore *semaphore() const |
| { return static_cast<interprocess_semaphore*>(m_shmem.get_user_address()); } |
| |
| detail::managed_open_or_create_impl<shared_memory_object> m_shmem; |
| typedef detail::named_creation_functor<interprocess_semaphore, int> construct_func_t; |
| #endif |
| /// @endcond |
| }; |
| |
| /// @cond |
| |
| #if defined(BOOST_INTERPROCESS_NAMED_SEMAPHORE_USES_POSIX_SEMAPHORES) |
| |
| inline named_semaphore::named_semaphore |
| (create_only_t, const char *name, unsigned int initialCount, const permissions &perm) |
| : m_sem(detail::DoCreate, name, initialCount, perm) |
| {} |
| |
| inline named_semaphore::named_semaphore |
| (open_or_create_t, const char *name, unsigned int initialCount, const permissions &perm) |
| : m_sem(detail::DoOpenOrCreate, name, initialCount, perm) |
| {} |
| |
| inline named_semaphore::named_semaphore(open_only_t, const char *name) |
| : m_sem(detail::DoOpen, name, 1, permissions()) |
| {} |
| |
| inline named_semaphore::~named_semaphore() |
| {} |
| |
| inline void named_semaphore::dont_close_on_destruction() |
| { detail::interprocess_tester::dont_close_on_destruction(m_sem); } |
| |
| inline void named_semaphore::wait() |
| { m_sem.wait(); } |
| |
| inline void named_semaphore::post() |
| { m_sem.post(); } |
| |
| inline bool named_semaphore::try_wait() |
| { return m_sem.try_wait(); } |
| |
| inline bool named_semaphore::timed_wait(const boost::posix_time::ptime &abs_time) |
| { |
| if(abs_time == boost::posix_time::pos_infin){ |
| this->wait(); |
| return true; |
| } |
| return m_sem.timed_wait(abs_time); |
| } |
| |
| inline bool named_semaphore::remove(const char *name) |
| { return detail::named_semaphore_wrapper::remove(name); } |
| |
| #else |
| |
| inline named_semaphore::~named_semaphore() |
| {} |
| |
| inline void named_semaphore::dont_close_on_destruction() |
| { detail::interprocess_tester::dont_close_on_destruction(m_shmem); } |
| |
| inline named_semaphore::named_semaphore |
| (create_only_t, const char *name, unsigned int initialCount, const permissions &perm) |
| : m_shmem (create_only |
| ,name |
| ,sizeof(interprocess_semaphore) + |
| detail::managed_open_or_create_impl<shared_memory_object>:: |
| ManagedOpenOrCreateUserOffset |
| ,read_write |
| ,0 |
| ,construct_func_t(detail::DoCreate, initialCount) |
| ,perm) |
| {} |
| |
| inline named_semaphore::named_semaphore |
| (open_or_create_t, const char *name, unsigned int initialCount, const permissions &perm) |
| : m_shmem (open_or_create |
| ,name |
| ,sizeof(interprocess_semaphore) + |
| detail::managed_open_or_create_impl<shared_memory_object>:: |
| ManagedOpenOrCreateUserOffset |
| ,read_write |
| ,0 |
| ,construct_func_t(detail::DoOpenOrCreate, initialCount) |
| ,perm) |
| {} |
| |
| inline named_semaphore::named_semaphore |
| (open_only_t, const char *name) |
| : m_shmem (open_only |
| ,name |
| ,read_write |
| ,0 |
| ,construct_func_t(detail::DoOpen, 0)) |
| {} |
| |
| inline void named_semaphore::post() |
| { semaphore()->post(); } |
| |
| inline void named_semaphore::wait() |
| { semaphore()->wait(); } |
| |
| inline bool named_semaphore::try_wait() |
| { return semaphore()->try_wait(); } |
| |
| inline bool named_semaphore::timed_wait(const boost::posix_time::ptime &abs_time) |
| { |
| if(abs_time == boost::posix_time::pos_infin){ |
| this->wait(); |
| return true; |
| } |
| return semaphore()->timed_wait(abs_time); |
| } |
| |
| inline bool named_semaphore::remove(const char *name) |
| { return shared_memory_object::remove(name); } |
| |
| #endif |
| |
| /// @endcond |
| |
| } //namespace interprocess { |
| } //namespace boost { |
| |
| |
| #include <boost/interprocess/detail/config_end.hpp> |
| |
| #endif //BOOST_INTERPROCESS_NAMED_SEMAPHORE_HPP |