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116 lines
3.0 KiB
C++
116 lines
3.0 KiB
C++
//
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// SharedMemory.h
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//
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// $Id: //poco/1.4/Foundation/include/Poco/SharedMemory.h#2 $
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//
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// Library: Foundation
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// Package: Processes
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// Module: SharedMemory
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//
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// Definition of the SharedMemory class.
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//
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// Copyright (c) 2007, Applied Informatics Software Engineering GmbH.
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// and Contributors.
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//
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// SPDX-License-Identifier: BSL-1.0
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//
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#ifndef Foundation_SharedMemory_INCLUDED
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#define Foundation_SharedMemory_INCLUDED
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#include "Poco/Foundation.h"
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#include <algorithm>
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#include <cstddef>
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namespace Poco {
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class SharedMemoryImpl;
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class File;
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class Foundation_API SharedMemory
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/// Create and manage a shared memory object.
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///
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/// A SharedMemory object has value semantics, but
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/// is implemented using a handle/implementation idiom.
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/// Therefore, multiple SharedMemory objects can share
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/// a single, reference counted SharedMemoryImpl object.
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{
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public:
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enum AccessMode
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{
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AM_READ = 0,
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AM_WRITE
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};
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SharedMemory();
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/// Default constructor creates an unmapped SharedMemory object.
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/// No clients can connect to an unmapped SharedMemory object.
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SharedMemory(const std::string& name, std::size_t size, AccessMode mode, const void* addrHint = 0, bool server = true);
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/// Creates or connects to a shared memory object with the given name.
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///
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/// For maximum portability, name should be a valid Unix filename and not
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/// contain any slashes or backslashes.
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///
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/// An address hint can be passed to the system, specifying the desired
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/// start address of the shared memory area. Whether the hint
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/// is actually honored is, however, up to the system. Windows platform
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/// will generally ignore the hint.
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///
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/// If server is set to true, the shared memory region will be unlinked
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/// by calling shm_unlink() (on POSIX platforms) when the SharedMemory object is destroyed.
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/// The server parameter is ignored on Windows platforms.
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SharedMemory(const File& file, AccessMode mode, const void* addrHint = 0);
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/// Maps the entire contents of file into a shared memory segment.
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///
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/// An address hint can be passed to the system, specifying the desired
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/// start address of the shared memory area. Whether the hint
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/// is actually honored is, however, up to the system. Windows platform
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/// will generally ignore the hint.
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SharedMemory(const SharedMemory& other);
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/// Creates a SharedMemory object by copying another one.
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~SharedMemory();
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/// Destroys the SharedMemory.
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SharedMemory& operator = (const SharedMemory& other);
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/// Assigns another SharedMemory object.
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void swap(SharedMemory& other);
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/// Swaps the SharedMemory object with another one.
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char* begin() const;
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/// Returns the start address of the shared memory segment.
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/// Will be NULL for illegal segments.
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char* end() const;
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/// Returns the one-past-end end address of the shared memory segment.
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/// Will be NULL for illegal segments.
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private:
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SharedMemoryImpl* _pImpl;
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};
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//
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// inlines
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//
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inline void SharedMemory::swap(SharedMemory& other)
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{
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using std::swap;
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swap(_pImpl, other._pImpl);
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}
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} // namespace Poco::Poco
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#endif // Foundation_SharedMemory_INCLUDED
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