Ticket #13626: main.cpp

#include <new>
#include <cstdio>
#include <cstdlib>

#include <iostream>

#include <memory>
#include <string>
#include <boost/interprocess/sync/mutex_family.hpp>
#include <boost/interprocess/indexes/null_index.hpp>
#include <boost/interprocess/managed_mapped_file.hpp>

class Test
{
public:
    Test *test;
};

typedef boost::interprocess::basic_managed_mapped_file <
    char,
    boost::interprocess::rbtree_best_fit <
        boost::interprocess::null_mutex_family,
        boost::interprocess::offset_ptr<void>
    >,
    boost::interprocess::null_index
> memory_mapped_file;

void* operator new(size_t size, memory_mapped_file &a)
{
    return a.allocate(size);
}

int main()
{
    using namespace boost::interprocess;
    //Remove shared memory on construction and destruction
    struct shm_remove
    {
        shm_remove() { std::remove("MySharedMemory"); }
        ~shm_remove(){ std::remove("MySharedMemory"); }
    } remover;

    Test *p;

    {
        //Create a managed shared memory
        memory_mapped_file shm(create_only, "MySharedMemory", 10000);

        //Check size
        std::cout << shm.get_size() << '\n';
        p = new(shm) Test();
        p->test = new(shm) Test();

        //Check pointers
        std::cout << "before growing:" << '\n';
        std::cout << "size: " << shm.get_size() << '\n';
        std::cout << "p is owned: " << shm.belongs_to_segment(p) << '\n';
        std::cout << "p->test is owned: " << shm.belongs_to_segment(p->test) << '\n';
        std::cout << "p->test = " << p->test << '\n';
    }
    {
        //Now that the segment is not mapped grow it adding extra 500 bytes
        memory_mapped_file::grow("MySharedMemory", 7*500);

        //Map it again
        memory_mapped_file shm(open_only, "MySharedMemory");
        //Check pointers
        std::cout << "after growing" << '\n';
        std::cout << "size: " << shm.get_size() << '\n';
        std::cout << "p is owned: " << shm.belongs_to_segment(p) << '\n';
        std::cout << "p->test is owned: " << shm.belongs_to_segment(p->test) << '\n';
        std::cout << "p->test = " << p->test << '\n';
    }
    return 0;
}