Question

我只是使用boost :: interprocess :: managed_shared_memory在内存中创建共享向量，我已经成功创建了共享内存，我发现当我读取向量时，可以读取和打印所有元素注释1中的向量，但是当离开向量g / gr的初始化范围时，即在main函数中，我不能再访问向量内容了，程序说地址映射错误，但是地址是一样的，为什么？谁有人回答？谢谢！

#include <boost/interprocess/managed_shared_memory.hpp>
#include <boost/interprocess/containers/vector.hpp>
#include <boost/interprocess/allocators/allocator.hpp>

typedef boost::interprocess::allocator<boost::interprocess::vector<int>, boost::interprocess::managed_shared_memory::segment_manager> ShmemAllocator;
typedef boost::interprocess::vector<boost::interprocess::vector<int>, ShmemAllocator> Shmem2DVector;

class TestVector{
public:
    Shmem2DVector *g;
    Shmem2DVector *gr;

    TestVector{
        boost::interprocess::managed_shared_memory segment(boost::interprocess::open_only, "shmem");
        g = segment.find<Shmem2DVector>("myVector").first;
        gr = segment.find<Shmem2DVector>("myVector").first;

        //1. print vector g/gr and size of vector g/gr
    }
};

int main(){
    TestVector test_vec();
    //2. print vector g/gr and size of vector g/gr
    return 0;
}

Answer 1

一旦离开构造函数，managed_shared_memory对象就会被销毁。尝试将您的班级定义更改为以下内容：

class TestVector
{
public:
    Shmem2DVector *g;
    Shmem2DVector *gr;

    TestVector()
        : segment(boost::interprocess::open_only, "shmem")
    {

        g = segment.find<Shmem2DVector>("myVector").first;
        gr = segment.find<Shmem2DVector>("myVector").first;
    }

private:
    boost::interprocess::managed_shared_memory segment;        
};

Boost :: interprocess managed_shared_memory指针有效范围

1 个答案: