////////////////////////////////////////////////////////////////////////////// // // (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>