如何创建进程间容器的 boost 进程间向量? [英] How to I create a boost interprocess vector of interprocess containers?
问题描述
我喜欢创建一个包含进程间容器的类的 boost 进程间向量.以下代码在调整大小函数调用之前有效,当然因为我的类没有默认构造函数.我该如何解决这个问题?该示例基于 boost 容器的容器 示例
I like to create a boost interprocess vector of classes containing a interprocess container. The following code works until the resize function call and of course because my class has not default constructor. How to I resolve this problem? The example is based on the boost Containers of containers example
谢谢马库斯
#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;
}
推荐答案
REWRITE
由于 Boost Containers 支持作用域分配器模式,您可以只使用作用域分配器,当该元素具有 uses_allocator<>
trait 对它有积极的作用:
As Boost Containers support the scoped allocator pattern, you can just use a scoped allocator, and the container will automatically pass it on internal construction (or emplacing) of new elements, when that element has the uses_allocator<>
trait specialized positively 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();
}
请注意我如何重新绑定 void_allocator
类型的分配器定义,从而更容易更改代码的根分配器"实现.
Note how I made the allocator definitions rebinds of the void_allocator
type, making it much easier to change the 'root allocator' implementation for your code.
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