1 | // |
2 | // NamedMutex.h |
3 | // |
4 | // Library: Foundation |
5 | // Package: Processes |
6 | // Module: NamedMutex |
7 | // |
8 | // Definition of the NamedMutex class. |
9 | // |
10 | // Copyright (c) 2004-2006, Applied Informatics Software Engineering GmbH. |
11 | // and Contributors. |
12 | // |
13 | // SPDX-License-Identifier: BSL-1.0 |
14 | // |
15 | |
16 | |
17 | #ifndef Foundation_NamedMutex_INCLUDED |
18 | #define Foundation_NamedMutex_INCLUDED |
19 | |
20 | |
21 | #include "Poco/Foundation.h" |
22 | #include "Poco/ScopedLock.h" |
23 | |
24 | |
25 | #if defined(POCO_OS_FAMILY_WINDOWS) |
26 | #include "Poco/NamedMutex_WIN32.h" |
27 | #elif defined(POCO_ANDROID) |
28 | #include "Poco/NamedMutex_Android.h" |
29 | #elif defined(POCO_OS_FAMILY_UNIX) |
30 | #include "Poco/NamedMutex_UNIX.h" |
31 | #else |
32 | #include "Poco/NamedMutex_VMS.h" |
33 | #endif |
34 | |
35 | |
36 | namespace Poco { |
37 | |
38 | |
39 | class Foundation_API NamedMutex: private NamedMutexImpl |
40 | /// A NamedMutex (mutual exclusion) is a global synchronization |
41 | /// mechanism used to control access to a shared resource |
42 | /// in a concurrent (multi process) scenario. |
43 | /// Using the ScopedLock class is the preferred way to automatically |
44 | /// lock and unlock a mutex. |
45 | /// |
46 | /// Unlike a Mutex or a FastMutex, which itself is the unit of synchronization, |
47 | /// a NamedMutex refers to a named operating system resource being the |
48 | /// unit of synchronization. |
49 | /// In other words, there can be multiple instances of NamedMutex referring |
50 | /// to the same actual synchronization object. |
51 | /// |
52 | /// |
53 | /// There should not be more than one instance of NamedMutex for |
54 | /// a given name in a process. Otherwise, the instances may |
55 | /// interfere with each other. |
56 | { |
57 | public: |
58 | typedef Poco::ScopedLock<NamedMutex> ScopedLock; |
59 | |
60 | NamedMutex(const std::string& name); |
61 | /// creates the Mutex. |
62 | |
63 | ~NamedMutex(); |
64 | /// destroys the Mutex. |
65 | |
66 | void lock(); |
67 | /// Locks the mutex. Blocks if the mutex |
68 | /// is held by another process or thread. |
69 | |
70 | bool tryLock(); |
71 | /// Tries to lock the mutex. Returns false immediately |
72 | /// if the mutex is already held by another process or thread. |
73 | /// Returns true if the mutex was successfully locked. |
74 | |
75 | void unlock(); |
76 | /// Unlocks the mutex so that it can be acquired by |
77 | /// other threads. |
78 | |
79 | private: |
80 | NamedMutex(); |
81 | NamedMutex(const NamedMutex&); |
82 | NamedMutex& operator = (const NamedMutex&); |
83 | }; |
84 | |
85 | |
86 | // |
87 | // inlines |
88 | // |
89 | inline void NamedMutex::lock() |
90 | { |
91 | lockImpl(); |
92 | } |
93 | |
94 | |
95 | inline bool NamedMutex::tryLock() |
96 | { |
97 | return tryLockImpl(); |
98 | } |
99 | |
100 | |
101 | inline void NamedMutex::unlock() |
102 | { |
103 | unlockImpl(); |
104 | } |
105 | |
106 | |
107 | } // namespace Poco |
108 | |
109 | |
110 | #endif // Foundation_NamedMutex_INCLUDED |
111 | |