1//
2// SharedMemoryImpl.h
3//
4// Library: Foundation
5// Package: Processes
6// Module: SharedMemoryImpl
7//
8// Definition of the SharedMemoryImpl class.
9//
10// Copyright (c) 2007, Applied Informatics Software Engineering GmbH.
11// and Contributors.
12//
13// SPDX-License-Identifier: BSL-1.0
14//
15
16
17#ifndef Foundation_SharedMemoryImpl_INCLUDED
18#define Foundation_SharedMemoryImpl_INCLUDED
19
20
21#include "Poco/Foundation.h"
22#include "Poco/SharedMemory.h"
23#include "Poco/RefCountedObject.h"
24
25
26namespace Poco {
27
28
29class Foundation_API SharedMemoryImpl: public RefCountedObject
30 /// Shared memory implementation for POSIX platforms.
31{
32public:
33 SharedMemoryImpl(const std::string& name, std::size_t size, SharedMemory::AccessMode mode, const void* addrHint, bool server);
34 /// Creates or connects to a shared memory object with the given name.
35 ///
36 /// For maximum portability, name should be a valid Unix filename and not
37 /// contain any slashes or backslashes.
38 ///
39 /// An address hint can be passed to the system, specifying the desired
40 /// start address of the shared memory area. Whether the hint
41 /// is actually honored is, however, up to the system. Windows platform
42 /// will generally ignore the hint.
43 ///
44 /// If server is set to false, the shared memory region will be unlinked
45 /// by calling shm_unlink when the SharedMemory object is destroyed.
46
47 SharedMemoryImpl(const Poco::File& file, SharedMemory::AccessMode mode, const void* addrHint);
48 /// Maps the entire contents of file into a shared memory segment.
49 ///
50 /// An address hint can be passed to the system, specifying the desired
51 /// start address of the shared memory area. Whether the hint
52 /// is actually honored is, however, up to the system. Windows platform
53 /// will generally ignore the hint.
54
55 char* begin() const;
56 /// Returns the start address of the shared memory segment.
57
58 char* end() const;
59 /// Returns the one-past-end end address of the shared memory segment.
60
61protected:
62 void map(const void* addrHint);
63 /// Maps the shared memory object.
64
65 void unmap();
66 /// Unmaps the shared memory object.
67
68 void close();
69 /// Releases the handle for the shared memory segment.
70
71 ~SharedMemoryImpl();
72 /// Destroys the SharedMemoryImpl.
73
74private:
75 SharedMemoryImpl();
76 SharedMemoryImpl(const SharedMemoryImpl&);
77 SharedMemoryImpl& operator = (const SharedMemoryImpl&);
78
79 std::size_t _size;
80 int _fd;
81 char* _address;
82 SharedMemory::AccessMode _access;
83 std::string _name;
84 bool _fileMapped;
85 bool _server;
86};
87
88
89//
90// inlines
91//
92inline char* SharedMemoryImpl::begin() const
93{
94 return _address;
95}
96
97
98inline char* SharedMemoryImpl::end() const
99{
100 return _address + _size;
101}
102
103
104} // namespace Poco
105
106
107#endif // Foundation_SharedMemoryImpl_INCLUDED
108