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76 lines
2.9 KiB
C++
76 lines
2.9 KiB
C++
//////////////////////////////////////////////////////////////////////////////
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//
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// (C) Copyright Ion Gaztanaga 2006-2008. 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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#include <boost/interprocess/detail/config_begin.hpp>
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//[doc_managed_copy_on_write
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#include <boost/interprocess/managed_mapped_file.hpp>
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#include <fstream> //std::fstream
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#include <iterator>//std::distance
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int main()
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{
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using namespace boost::interprocess;
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//Try to erase any previous managed segment with the same name
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file_mapping::remove("MyManagedFile");
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file_mapping::remove("MyManagedFile2");
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remove_file_on_destroy destroyer1("MyManagedFile");
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remove_file_on_destroy destroyer2("MyManagedFile2");
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{
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//Create an named integer in a managed mapped file
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managed_mapped_file managed_file(create_only, "MyManagedFile", 65536);
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managed_file.construct<int>("MyInt")(0u);
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//Now create a copy on write version
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managed_mapped_file managed_file_cow(open_copy_on_write, "MyManagedFile");
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//Erase the int and create a new one
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if(!managed_file_cow.destroy<int>("MyInt"))
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throw int(0);
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managed_file_cow.construct<int>("MyInt2");
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//Check changes
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if(managed_file_cow.find<int>("MyInt").first && !managed_file_cow.find<int>("MyInt2").first)
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throw int(0);
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//Check the original is intact
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if(!managed_file.find<int>("MyInt").first && managed_file.find<int>("MyInt2").first)
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throw int(0);
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{ //Dump the modified copy on write segment to a file
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std::fstream file("MyManagedFile2", std::ios_base::out | std::ios_base::binary);
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if(!file)
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throw int(0);
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file.write(static_cast<const char *>(managed_file_cow.get_address()), managed_file_cow.get_size());
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}
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//Now open the modified file and test changes
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managed_mapped_file managed_file_cow2(open_only, "MyManagedFile2");
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if(managed_file_cow2.find<int>("MyInt").first && !managed_file_cow2.find<int>("MyInt2").first)
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throw int(0);
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}
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{
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//Now create a read-only version
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managed_mapped_file managed_file_ro(open_read_only, "MyManagedFile");
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//Check the original is intact
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if(!managed_file_ro.find<int>("MyInt").first && managed_file_ro.find<int>("MyInt2").first)
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throw int(0);
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//Check the number of named objects using the iterators
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if(std::distance(managed_file_ro.named_begin(), managed_file_ro.named_end()) != 1 &&
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std::distance(managed_file_ro.unique_begin(), managed_file_ro.unique_end()) != 0 )
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throw int(0);
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}
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return 0;
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}
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//]
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#include <boost/interprocess/detail/config_end.hpp>
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