Automatic unlocking of interprocess_mutex with scoped_lock

bitest4.cpp

#include <boost/interprocess/managed_xsi_shared_memory.hpp>
#include <boost/interprocess/xsi_key.hpp>
#include <boost/interprocess/sync/scoped_lock.hpp>
#include <iostream>

using namespace boost::interprocess;

void first_process(managed_xsi_shared_memory *shm);
void second_process(managed_xsi_shared_memory *shm);

int main()
{
    managed_xsi_shared_memory *shm = nullptr;

    try {
        shm = new managed_xsi_shared_memory{ create_only, xsi_key("bitest4.cpp", 239), 1024 };
        first_process(shm);
    } catch (interprocess_exception& e) {
        shm = new managed_xsi_shared_memory{ open_only, xsi_key("bitest4.cpp", 239) };
        second_process(shm);
    }
}

void first_process(managed_xsi_shared_memory *shm)
{
    std::cout << "This is the first process." << std::endl;

    interprocess_mutex *mtx = shm->find_or_construct<interprocess_mutex>("gMutex")();

    scoped_lock<interprocess_mutex> lock(*mtx);

    std::cout << "The first process locked an interprocess_mutex" << std::endl;
    std::cout << "and is going to exit without unlocking the mutex" << std::endl;
}

void second_process(managed_xsi_shared_memory *shm)
{
    std::cout << "This is the second process." << std::endl;

    interprocess_mutex *mtx = shm->find_or_construct<interprocess_mutex>("gMutex")();
    
    std::cout << "The second process is going to lock an interprocess mutex," << std::endl;
    std::cout << "and if it succeeds, then a message will be shown." << std::endl;
    std::cout << "If it failes, it will run indefinitely." << std::endl;

    scoped_lock<interprocess_mutex> lock(*mtx);

    std::cout << "The second process locked the mutex!" << std::endl;
}