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1 | ////////////////////////////////////////////////////////////////////////////// |
2 | // | |
3 | // (C) Copyright Ion Gaztanaga 2005-2012. Distributed under the Boost | |
4 | // Software License, Version 1.0. (See accompanying file | |
5 | // LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
6 | // | |
7 | // See http://www.boost.org/libs/interprocess for documentation. | |
8 | // | |
9 | ////////////////////////////////////////////////////////////////////////////// | |
10 | ||
11 | #ifndef BOOST_INTERPROCESS_NAMED_SEMAPHORE_HPP | |
12 | #define BOOST_INTERPROCESS_NAMED_SEMAPHORE_HPP | |
13 | ||
14 | #ifndef BOOST_CONFIG_HPP | |
15 | # include <boost/config.hpp> | |
16 | #endif | |
17 | # | |
18 | #if defined(BOOST_HAS_PRAGMA_ONCE) | |
19 | # pragma once | |
20 | #endif | |
21 | ||
22 | #include <boost/interprocess/detail/config_begin.hpp> | |
23 | #include <boost/interprocess/detail/workaround.hpp> | |
24 | #include <boost/interprocess/creation_tags.hpp> | |
25 | #include <boost/interprocess/exceptions.hpp> | |
26 | #include <boost/interprocess/permissions.hpp> | |
27 | #include <boost/interprocess/detail/interprocess_tester.hpp> | |
28 | #include <boost/interprocess/detail/posix_time_types_wrk.hpp> | |
29 | ||
30 | #if defined(BOOST_INTERPROCESS_NAMED_SEMAPHORE_USES_POSIX_SEMAPHORES) | |
31 | #include <boost/interprocess/sync/posix/named_semaphore.hpp> | |
32 | //Experimental... | |
33 | #elif !defined(BOOST_INTERPROCESS_FORCE_GENERIC_EMULATION) && defined (BOOST_INTERPROCESS_WINDOWS) | |
34 | #include <boost/interprocess/sync/windows/named_semaphore.hpp> | |
35 | #define BOOST_INTERPROCESS_USE_WINDOWS | |
36 | #else | |
37 | #include <boost/interprocess/sync/shm/named_semaphore.hpp> | |
38 | #endif | |
39 | ||
40 | //!\file | |
41 | //!Describes a named semaphore class for inter-process synchronization | |
42 | ||
43 | namespace boost { | |
44 | namespace interprocess { | |
45 | ||
46 | //!A semaphore with a global name, so it can be found from different | |
47 | //!processes. Allows several resource sharing patterns and efficient | |
48 | //!acknowledgment mechanisms. | |
49 | class named_semaphore | |
50 | { | |
51 | #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED) | |
52 | ||
53 | //Non-copyable | |
54 | named_semaphore(); | |
55 | named_semaphore(const named_semaphore &); | |
56 | named_semaphore &operator=(const named_semaphore &); | |
57 | #endif //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED | |
58 | ||
59 | public: | |
60 | //!Creates a global semaphore with a name, and an initial count. | |
61 | //!If the semaphore can't be created throws interprocess_exception | |
62 | named_semaphore(create_only_t, const char *name, unsigned int initialCount, const permissions &perm = permissions()); | |
63 | ||
64 | //!Opens or creates a global semaphore with a name, and an initial count. | |
65 | //!If the semaphore is created, this call is equivalent to | |
66 | //!named_semaphore(create_only_t, ...) | |
67 | //!If the semaphore is already created, this call is equivalent to | |
68 | //!named_semaphore(open_only_t, ... ) | |
69 | //!and initialCount is ignored. | |
70 | named_semaphore(open_or_create_t, const char *name, unsigned int initialCount, const permissions &perm = permissions()); | |
71 | ||
72 | //!Opens a global semaphore with a name if that semaphore is previously. | |
73 | //!created. If it is not previously created this function throws | |
74 | //!interprocess_exception. | |
75 | named_semaphore(open_only_t, const char *name); | |
76 | ||
77 | //!Destroys *this and indicates that the calling process is finished using | |
78 | //!the resource. The destructor function will deallocate | |
79 | //!any system resources allocated by the system for use by this process for | |
80 | //!this resource. The resource can still be opened again calling | |
81 | //!the open constructor overload. To erase the resource from the system | |
82 | //!use remove(). | |
83 | ~named_semaphore(); | |
84 | ||
85 | //!Increments the semaphore count. If there are processes/threads blocked waiting | |
86 | //!for the semaphore, then one of these processes will return successfully from | |
87 | //!its wait function. If there is an error an interprocess_exception exception is thrown. | |
88 | void post(); | |
89 | ||
90 | //!Decrements the semaphore. If the semaphore value is not greater than zero, | |
91 | //!then the calling process/thread blocks until it can decrement the counter. | |
92 | //!If there is an error an interprocess_exception exception is thrown. | |
93 | void wait(); | |
94 | ||
95 | //!Decrements the semaphore if the semaphore's value is greater than zero | |
96 | //!and returns true. If the value is not greater than zero returns false. | |
97 | //!If there is an error an interprocess_exception exception is thrown. | |
98 | bool try_wait(); | |
99 | ||
100 | //!Decrements the semaphore if the semaphore's value is greater | |
101 | //!than zero and returns true. Otherwise, waits for the semaphore | |
102 | //!to the posted or the timeout expires. If the timeout expires, the | |
103 | //!function returns false. If the semaphore is posted the function | |
104 | //!returns true. If there is an error throws sem_exception | |
105 | bool timed_wait(const boost::posix_time::ptime &abs_time); | |
106 | ||
107 | //!Erases a named semaphore from the system. | |
108 | //!Returns false on error. Never throws. | |
109 | static bool remove(const char *name); | |
110 | ||
111 | #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED) | |
112 | private: | |
113 | friend class ipcdetail::interprocess_tester; | |
114 | void dont_close_on_destruction(); | |
115 | ||
116 | #if defined(BOOST_INTERPROCESS_NAMED_SEMAPHORE_USES_POSIX_SEMAPHORES) | |
117 | typedef ipcdetail::posix_named_semaphore impl_t; | |
118 | #elif defined(BOOST_INTERPROCESS_USE_WINDOWS) | |
119 | #undef BOOST_INTERPROCESS_USE_WINDOWS | |
120 | typedef ipcdetail::windows_named_semaphore impl_t; | |
121 | #else | |
122 | typedef ipcdetail::shm_named_semaphore impl_t; | |
123 | #endif | |
124 | impl_t m_sem; | |
125 | #endif //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED | |
126 | }; | |
127 | ||
128 | #if !defined(BOOST_INTERPROCESS_DOXYGEN_INVOKED) | |
129 | ||
130 | inline named_semaphore::named_semaphore | |
131 | (create_only_t, const char *name, unsigned int initialCount, const permissions &perm) | |
132 | : m_sem(create_only, name, initialCount, perm) | |
133 | {} | |
134 | ||
135 | inline named_semaphore::named_semaphore | |
136 | (open_or_create_t, const char *name, unsigned int initialCount, const permissions &perm) | |
137 | : m_sem(open_or_create, name, initialCount, perm) | |
138 | {} | |
139 | ||
140 | inline named_semaphore::named_semaphore(open_only_t, const char *name) | |
141 | : m_sem(open_only, name) | |
142 | {} | |
143 | ||
144 | inline named_semaphore::~named_semaphore() | |
145 | {} | |
146 | ||
147 | inline void named_semaphore::dont_close_on_destruction() | |
148 | { ipcdetail::interprocess_tester::dont_close_on_destruction(m_sem); } | |
149 | ||
150 | inline void named_semaphore::wait() | |
151 | { m_sem.wait(); } | |
152 | ||
153 | inline void named_semaphore::post() | |
154 | { m_sem.post(); } | |
155 | ||
156 | inline bool named_semaphore::try_wait() | |
157 | { return m_sem.try_wait(); } | |
158 | ||
159 | inline bool named_semaphore::timed_wait(const boost::posix_time::ptime &abs_time) | |
160 | { return m_sem.timed_wait(abs_time); } | |
161 | ||
162 | inline bool named_semaphore::remove(const char *name) | |
163 | { return impl_t::remove(name); } | |
164 | ||
165 | #endif //#ifndef BOOST_INTERPROCESS_DOXYGEN_INVOKED | |
166 | ||
167 | } //namespace interprocess { | |
168 | } //namespace boost { | |
169 | ||
170 | ||
171 | #include <boost/interprocess/detail/config_end.hpp> | |
172 | ||
173 | #endif //BOOST_INTERPROCESS_NAMED_SEMAPHORE_HPP |