////////////////////////////////////////////////////////////////////////////// // // (C) Copyright Ion Gaztanaga 2006-2012. 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 //[doc_complex_map_uses_allocator #include #include #include #include #include //<- #include "../test/get_process_id_name.hpp" //-> using namespace boost::interprocess; //Typedefs of allocators and containers typedef managed_shared_memory::segment_manager segment_manager_t; typedef allocator void_allocator; typedef allocator int_allocator; typedef boost::container::vector int_vector; typedef allocator int_vector_allocator; typedef boost::container::vector int_vector_vector; typedef allocator char_allocator; typedef boost::container::basic_string, char_allocator> char_string; class complex_data { int id_; char_string char_string_; int_vector_vector int_vector_vector_; public: //Mark this class as uses-allocator construction-ready (see Boost.Container's docs) //Boost.Interprocess machinery will pass the allocator argument automatically if //constructors takes the allocator_type as the last argument of constructors typedef void_allocator allocator_type; //Since void_allocator is convertible to any other allocator, we can simplify //the initialization taking just one allocator for all inner containers. complex_data(int id, const char *name, const void_allocator &void_alloc) : id_(id), char_string_(name, void_alloc), int_vector_vector_(void_alloc) {} //Other members... //<- int get_id() { return id_; }; char_string get_char_string() { return char_string_; }; int_vector_vector get_int_vector_vector() { return int_vector_vector_; }; //-> }; //A transparent comparison functor //Allows creating associative container `value_type`s from comparable //types (e.g. shared memory string types from "const char *" arguments) struct less_transparent { typedef void is_transparent; template bool operator() (const T &t, const U &u) const { return t < u; } }; //Definition of the map holding a string as key and complex_data as mapped type typedef std::pair map_value_type; typedef std::pair movable_to_map_value_type; typedef allocator map_value_type_allocator; typedef boost::container::map< char_string, complex_data , less_transparent, map_value_type_allocator> complex_map_type; int main () { //Remove shared memory on construction and destruction struct shm_remove { shm_remove() { shared_memory_object::remove(test::get_process_id_name()); } ~shm_remove(){ shared_memory_object::remove(test::get_process_id_name()); } } remover; //<- (void)remover; //-> //Create shared memory managed_shared_memory segment(create_only, test::get_process_id_name(), 65536); //Construct the shared memory map (associated with name "MyMap") and fill it using "extended uses allocator construction". //In this case "construct" tries to automatically pass the allocator argument to the constructed //type in addition to user-supplied arguments. "Uses-allocator construction" from the C++ standard // //In this case, no user arguments are provided, but the segment manager machinery has //detected that boost::container::map supports the user-allocator-construction protocol //so it automatically adds the allocator parameter and calls map::map(allocator_type) constructor. complex_map_type *mymap = segment.construct("MyMap")(); //This transparent insertion function plus uses-allocator construction so that //the programmer does not need to explicitly pass allocator instances. The container, //through boost::container::allocator::construct function, automatically adds the needed allocator //arguments without forcing the user to supply them, calling the following constructors: // //key_type --> basic_string(const char *, allocator_type) //mapped_type --> complex_data(int, const char *, allocator_type) // //The programmer only needs to specify the non-allocator arguments mymap->try_emplace("key_str", 3, "default_name"); return 0; } //]