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