c++ - 如何在 boost.interprocess 共享内存中使用复杂结构的 "push_back"函数 vector

Question

抱歉打扰了。 我正在编写代码，使这段代码，“http://coliru.stacked-crooked.com/a/0ab21481b69d87bb”在这个问题“Structures and vectors in Boost Shared Memory”中成为基础

但是，我陷入了这一行的编译错误。

data.push_back(id);   // 14 line in main function 

这个“data”val 没有匹配的“push_back”函数。 此 val 在此行中由“auto&”声明。

auto& data = Shared::locate(smt);   // 10 line in "while(1)" of main function

(这个 locate(smt) 函数是在共享内存中构造一个复杂结构的 vector )

我假设“数据”是复杂结构的 vector 或迭代器，但我知道没有办法运行这一行。

我想知道我在这段代码的某个地方错了，但我不知道在哪里。

请帮帮我

注意事项 1: “data.push_back(id);”行没有匹配调用'boost::container::vector, boost::interprocess::iset_index>> >, boost::interprocess::allocator, boost::interprocess::iset_index>> >, boost::interprocess::segment_manager, boost::interprocess::iset_index>> >::push_back(InData&)' 候选:void boost::container::vector::push_back(const T&) [with T = BasicInData, boost::interprocess::iset_index>> >; Allocator = boost::interprocess::allocator, boost::interprocess::iset_index>> >, boost::interprocess::segment_manager, boost::interprocess::iset_index>>]|

注意事项 2: 现在，我尝试更改为以下行；

cv::Mat_<cv::Vec3b> mat;
cv::VideoCapture vcap(0);

InData id(Shared::alloc<uchar_allocator>);
   // camera open check
if (!vcap.isOpened())
    return -1;

但是，另一个编译错误出现“'id' which is of non-class type”。 我觉得缺少什么。我该怎么办？

//  opencv's lib    
#include <cv.h>
#include <cxcore.h>
#include <highgui.h>
//  opencv's lib end
#include <string>
#include <boost/interprocess/managed_shared_memory.hpp>

#include <boost/interprocess/managed_mapped_file.hpp> // use for Coliru
#include <boost/interprocess/containers/vector.hpp>   // boost/containers/vector.hpp
#include <boost/interprocess/containers/string.hpp>   // boost/containers/string.hpp
#include <iostream>
#include <sys/time.h>
#include <stdio.h>

 //                                                                    void_allocator;
namespace bip = boost::interprocess;

typedef unsigned char uchar;
//Typedefs of allocators and containers
typedef bip::managed_shared_memory::segment_manager                       segment_manager_t;
typedef bip::allocator<void, segment_manager_t>  void_allocator;

typedef void_allocator::rebind<uchar>::other                           uchar_allocator;
typedef bip::vector<uchar, uchar_allocator>                                   uchar_vector;



template <typename Alloc = std::allocator<char> >
struct BasicInData {

    public:
        BasicInData(Alloc alloc = {}) : image(alloc)
        { }

        template <typename T>
        BasicInData(double x, int sizeImg, uchar_vector& image, Alloc alloc = {}) :
            x(x), sizeImg(sizeImg), image(alloc)
        { }

        double x = 0;
        int sizeImg = 0;
        uchar_vector image;
};

using InData = BasicInData<>; // just heap allocated

namespace Shared {
    using segment                      = bip::managed_shared_memory;
    using segment_manager              = segment::segment_manager;

    template <typename T> using alloc  = bip::allocator<T, segment_manager>;
    template <typename T> using vector = bip::vector<T, alloc<T> >;

    using InData = BasicInData<alloc<char> >; // shared memory version

    vector<InData>& locate(segment& smt) {
        auto* v = smt.find_or_construct<vector<InData> >("InDataVector")(smt.get_segment_manager());
        assert(v);
        return *v;
    }
}


int main(int argc, char* argv[]) {
    if(argc == 1){ //Parent process
        struct timeval tv;
        // there are making no sense 2 line in below, just examine
        gettimeofday(&tv, NULL);
        double time = ((double)tv.tv_usec/1000000);
        // Remove shared memory on construction and destruction

        // Create a new segment with given name and size
        struct shm_remove
        {
            shm_remove(){bip::shared_memory_object::remove("MySharedMemory");}
            ~shm_remove(){bip::shared_memory_object::remove("MySharedMemory");}
        }remover;
        Shared::segment smt(bip::create_only,"MySharedMemory", 65536); // 65536 for coliru
        auto& data = Shared::locate(smt);
        //Shared::alloc bip::alloc_inst (data);
        // Camera Capture 
        cv::Mat_<cv::Vec3b> mat;
        cv::VideoCapture vcap(0);

        InData id;
        // camera open check
        if (!vcap.isOpened())
            return -1;

        while (1) { // while keyboard key push
            vcap >> mat; // camera to mat
            int image_size = mat.total() * mat.elemSize();
            id.sizeImg = image_size;
            id.image.resize(image_size * sizeof(uchar));
            memcpy(&id.image[0], mat.data, image_size * sizeof(uchar));
            // get microsecond by double
            gettimeofday(&tv, NULL);
            double time = ((double)tv.tv_usec/1000000);
            id.x = time;
            data.push_back(id);
            if(cv::waitKey(30) >= 0) break; // keyboard pushed
        }
        //Launch child process
        std::string s(argv[0]); s += " child";
        if(0 != std::system(s.c_str()))
            return 1;

        // check child has destroyed the vector
        if(segment.find<vector<InData>>("InDataVector").first)
            return 1;
        }
    }else{
        // Open the managed segment
        managed_shared_memory segment(open_only, "MySharedMemory");

        // Find the vector 
        vector<InData> *myvector = segment.find<vector<InData>>("InDataVector").first;
        // Use vector in reverse order

        vector<InData>::iterator it;

        cv::Mat_<cv::Vec3b> im;
        for(it = myvector->begin(); it !=myvector->end(); ++it){
            im.resize(it->sizeImg);
            memcpy(im.data, &imref[0], it->sizeImg);
            cv::imshow("window1", im);
        }

        segment.destroy<vector<InData>>("InDataVector");

        return 0;
    }
}

Answer 1

谢谢大家的帮助。 终于搞定了。

main函数中的这一行是

InData id;

改为

Shared::InData id(smt.get_segment_manager());

这是完整的代码。

#include <cv.h>
#include <cxcore.h>
#include <highgui.h>
#include <boost/interprocess/managed_shared_memory.hpp>
#include <boost/interprocess/managed_mapped_file.hpp> // use for Coliru
#include <boost/interprocess/containers/vector.hpp>   // boost/containers/vector.hpp
#include <boost/interprocess/containers/string.hpp>   // boost/containers/string.hpp
#include <iostream>
#include <sys/time.h>
#include <stdio.h>

 //                                                                    void_allocator;
namespace bip = boost::interprocess;

typedef unsigned char uchar;
//Typedefs of allocators and containers
typedef bip::managed_shared_memory::segment_manager                       segment_manager_t;
typedef bip::allocator<void, segment_manager_t>  void_allocator;

typedef void_allocator::rebind<uchar>::other                           uchar_allocator;
typedef bip::vector<uchar, uchar_allocator>                                   uchar_vector;



template <typename Alloc = std::allocator<uchar> >
struct BasicInData {

    public:
        BasicInData(Alloc alloc = {}) : image(alloc)
        { }

        template <typename T>
        BasicInData(double x, int sizeImg, uchar_vector& image, Alloc alloc = {}) :
            x(x), sizeImg(sizeImg), image(alloc)
        { }

        double x = 0;
        int sizeImg = 0;
        uchar_vector image;
};

using InData = BasicInData<>; // just heap allocated

namespace Shared {
    using segment                      = bip::managed_shared_memory;
    using segment_manager              = segment::segment_manager;

    template <typename T> using alloc  = bip::allocator<T, segment_manager>;
    template <typename T> using vector = bip::vector<T, alloc<T> >;

    using InData = BasicInData<alloc<uchar> >; // shared memory version

    vector<InData>& locate(segment& smt) {
        auto* v = smt.find_or_construct<vector<InData> >("InDataVector")(smt.get_segment_manager());
        assert(v);
        return *v;
    }
}


int main(int argc, char* argv[]) {
    if(argc == 1){ //Parent process
        // Remove shared memory on construction and destruction

        // Create a new segment with given name and size
        struct timeval tv;
        gettimeofday(&tv, NULL);
        struct shm_remove
        {
            shm_remove(){bip::shared_memory_object::remove("MySharedMemory");}
            ~shm_remove(){bip::shared_memory_object::remove("MySharedMemory");}
        }remover;
        Shared::segment smt(bip::create_only,"MySharedMemory", 65536); // 10 Kb for coliru
        auto &data = Shared::locate(smt);
        //Shared::alloc bip::alloc_inst (data);

        cv::Mat_<cv::Vec3b> mat;
        cv::VideoCapture vcap(0);

        Shared::InData id(smt.get_segment_manager());


        if (!vcap.isOpened())
            return -1;

        while (1) {
            vcap >> mat;
            int image_size = mat.total() * mat.elemSize();
            id.sizeImg = image_size;
            id.image.resize(image_size * sizeof(uchar));
            memcpy(&id.image[0], mat.data, image_size * sizeof(uchar));
            //Launch child process
            gettimeofday(&tv, NULL);
            double time = ((double)tv.tv_usec/1000000);
            id.x = time;
            data.push_back(id);
            if(cv::waitKey(30) >= 0) break;
        }

        std::string s(argv[0]); s += " child";
        if(0 != std::system(s.c_str()))
            return 1;

        // check child has destroyed the vector
        if(smt.find<Shared::vector<InData>>("InDataVector").first)
            return 1;

    } else{
        // Open the managed segment
        bip::managed_shared_memory segment(bip::open_only, "MySharedMemory");

        // Find the vector using c-string name
        bip::vector<InData> *myvector = segment.find<bip::vector<InData>>("InDataVector").first;
        // Use vector in reverse order

        bip::vector<InData>::iterator it;

        cv::Mat_<cv::Vec3b> im;
        for(it = myvector->begin(); it !=myvector->end(); ++it){
            im.resize(it->sizeImg);
            memcpy(im.data, &it->image[0], it->sizeImg);
            cv::imshow("window1", im);
        }

        segment.destroy<bip::vector<InData>>("InDataVector");

        return 0;
    }
}