How to create a vector of interprocess acceleration of interprocessor containers?
I like to create interprocess acceleration vectors for classes that contain an interprocess communication container. The following code works prior to calling the resize function and of course because my class does not have a default constructor. How to solve this problem? The example is based on the container containers example
Thanks Marcus
#include <boost/interprocess/managed_shared_memory.hpp>
#include <boost/interprocess/allocators/allocator.hpp>
#include <boost/interprocess/containers/map.hpp>
#include <boost/interprocess/containers/vector.hpp>
#include <boost/interprocess/containers/string.hpp>
using namespace boost::interprocess;
//Typedefs of allocators and containers
typedef managed_shared_memory::segment_manager segment_manager_t;
typedef allocator<void, segment_manager_t> void_allocator;
typedef allocator<int, segment_manager_t> int_allocator;
typedef vector<int, int_allocator> int_vector;
typedef allocator<char, segment_manager_t> char_allocator;
typedef basic_string<char, std::char_traits<char>, char_allocator> char_string;
class complex_data
{
public:
int id_;
char_string char_string_;
int_vector int_vector_;
//Since void_allocator is convertible to any other allocator<T>, we can simplify
//the initialization taking just one allocator for all inner containers.
complex_data(const void_allocator &void_alloc)
: id_(-1), char_string_(void_alloc), int_vector_(void_alloc)
{}
//Other members...
};
typedef allocator<complex_data, segment_manager_t> complex_data_allocator;
typedef vector<complex_data, complex_data_allocator> complex_data_vector;
int main ()
{
//Remove shared memory on construction and destruction
struct shm_remove
{
shm_remove() { shared_memory_object::remove("MySharedMemory"); }
~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }
} remover;
//Create shared memory
managed_shared_memory segment(create_only,"MySharedMemory", 65536);
//An allocator convertible to any allocator<T, segment_manager_t> type
void_allocator alloc_inst (segment.get_segment_manager());
//Construct the shared memory map and fill it
complex_data *complex_data0_ = segment.construct<complex_data> ("MyCompexData")(alloc_inst);
complex_data0_->char_string_ = "Hello Wold";
complex_data0_->int_vector_.push_back(3);
complex_data *complex_data1_ = segment.find_or_construct<complex_data> ("MyCompexData")(alloc_inst);
complex_data1_->int_vector_.push_back(6);
std::cout << complex_data1_->id_ << ", " << complex_data0_->char_string_;
for(size_t i = 0; i < complex_data1_->int_vector_.size(); i++) std::cout << ", " << complex_data1_->int_vector_[i];
complex_data_vector *complex_data_vector0 = segment.construct<complex_data_vector> ("MyCompexDataVector")(alloc_inst);
/**
* Problem
* How to I resize or add new elements?
**/
complex_data_vector0->resize(3);
return 0;
}
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1 answer
REWRITE
Since Boost Containers support copied allocator pattern, you can simply use a distributed allocator and the container will automatically pass it to the internal construct (or replacement) of new elements when that element has a trait uses_allocator<>
that is positively tuned for it:
#include <boost/interprocess/managed_shared_memory.hpp>
#include <boost/container/scoped_allocator.hpp>
#include <boost/interprocess/allocators/allocator.hpp>
#include <boost/interprocess/containers/map.hpp>
#include <boost/interprocess/containers/vector.hpp>
#include <boost/interprocess/containers/string.hpp>
using namespace boost::interprocess;
//Typedefs of allocators and containers
typedef managed_shared_memory::segment_manager segment_manager_t;
typedef boost::container::scoped_allocator_adaptor<allocator<void, segment_manager_t> >
void_allocator;
typedef void_allocator::rebind<int>::other int_allocator;
typedef vector<int, int_allocator> int_vector;
typedef void_allocator::rebind<char>::other char_allocator;
typedef basic_string<char, std::char_traits<char>, char_allocator> char_string;
class complex_data
{
public:
int id_;
char_string char_string_;
int_vector int_vector_;
//Since void_allocator is convertible to any other allocator<T>, we can simplify
//the initialization taking just one allocator for all inner containers.
typedef void_allocator allocator_type;
complex_data(complex_data const& other, const allocator_type &void_alloc)
: id_(other.id_), char_string_(other.char_string_, void_alloc), int_vector_(other.int_vector_, void_alloc)
{}
complex_data(const allocator_type &void_alloc)
: id_(-1), char_string_(void_alloc), int_vector_(void_alloc)
{}
//Other members...
//
};
typedef void_allocator::rebind<complex_data>::other complex_data_allocator;
typedef vector<complex_data, complex_data_allocator> complex_data_vector;
int main ()
{
//Remove shared memory on construction and destruction
struct shm_remove
{
shm_remove() { shared_memory_object::remove("MySharedMemory"); }
~shm_remove(){ shared_memory_object::remove("MySharedMemory"); }
} remover;
//Create shared memory
managed_shared_memory segment(create_only,"MySharedMemory", 65536);
//An allocator convertible to any allocator<T, segment_manager_t> type
void_allocator alloc_inst (segment.get_segment_manager());
//Construct the shared memory map and fill it
complex_data *complex_data0_ = segment.construct<complex_data> ("MyCompexData")(alloc_inst);
complex_data0_->char_string_ = "Hello Wold";
complex_data0_->int_vector_.push_back(3);
complex_data *complex_data1_ = segment.find_or_construct<complex_data> ("MyCompexData")(alloc_inst);
complex_data1_->int_vector_.push_back(6);
std::cout << complex_data1_->id_ << ", " << complex_data0_->char_string_;
for(size_t i = 0; i < complex_data1_->int_vector_.size(); i++) std::cout << ", " << complex_data1_->int_vector_[i];
complex_data_vector *complex_data_vector0 = segment.construct<complex_data_vector> ("MyCompexDataVector")(alloc_inst);
complex_data_vector0->resize(3);
complex_data_vector0->emplace_back();
}
Note how I made overrides of type allocator definitions void_allocator
, which made it much easier to implement a root allocator implementation for your code.
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