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//////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2006-2009. Distributed under the Boost
// Software License, Version 1.0. (See accompanying file
// LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/interprocess for documentation.
//
//////////////////////////////////////////////////////////////////////////////
#include <boost/interprocess/detail/config_begin.hpp>
//[doc_managed_copy_on_write
#include <boost/interprocess/managed_mapped_file.hpp>
#include <fstream> //std::fstream
#include <iterator>//std::distance
int main()
{
using namespace boost::interprocess;
//Try to erase any previous managed segment with the same name
file_mapping::remove("MyManagedFile");
file_mapping::remove("MyManagedFile2");
remove_file_on_destroy destroyer1("MyManagedFile");
remove_file_on_destroy destroyer2("MyManagedFile2");
{
//Create an named integer in a managed mapped file
managed_mapped_file managed_file(create_only, "MyManagedFile", 65536);
managed_file.construct<int>("MyInt")(0u);
//Now create a copy on write version
managed_mapped_file managed_file_cow(open_copy_on_write, "MyManagedFile");
//Erase the int and create a new one
if(!managed_file_cow.destroy<int>("MyInt"))
throw int(0);
managed_file_cow.construct<int>("MyInt2");
//Check changes
if(managed_file_cow.find<int>("MyInt").first && !managed_file_cow.find<int>("MyInt2").first)
throw int(0);
//Check the original is intact
if(!managed_file.find<int>("MyInt").first && managed_file.find<int>("MyInt2").first)
throw int(0);
{ //Dump the modified copy on write segment to a file
std::fstream file("MyManagedFile2", std::ios_base::out | std::ios_base::binary);
if(!file)
throw int(0);
file.write(static_cast<const char *>(managed_file_cow.get_address()), managed_file_cow.get_size());
}
//Now open the modified file and test changes
managed_mapped_file managed_file_cow2(open_only, "MyManagedFile2");
if(managed_file_cow2.find<int>("MyInt").first && !managed_file_cow2.find<int>("MyInt2").first)
throw int(0);
}
{
//Now create a read-only version
managed_mapped_file managed_file_ro(open_read_only, "MyManagedFile");
//Check the original is intact
if(!managed_file_ro.find<int>("MyInt").first && managed_file_ro.find<int>("MyInt2").first)
throw int(0);
//Check the number of named objects using the iterators
if(std::distance(managed_file_ro.named_begin(), managed_file_ro.named_end()) != 1 &&
std::distance(managed_file_ro.unique_begin(), managed_file_ro.unique_end()) != 0 )
throw int(0);
}
return 0;
}
//]
#include <boost/interprocess/detail/config_end.hpp>
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