static bool some_condition = false;

void thread_disposed(const omni::thread* sender)
{
    std::cout << "Thread " << sender->id() << " is being destroyed." << std::endl;
    some_condition = true;
    sender->join();
}

void thread_function()
{
    do {
        // thread code ...
    } while (!some_condition);
}

void some_function()
{
    omni::thread t(&thread_function);
    t.disposing += &thread_disposed;
    t.start();
}

int main()
{
    std::cout << "before" << std::endl;
    some_function()
    // thread destructor called when scope is left from
    // some_function, thus the disposed function will
    // be called calling our attached thread_disposed function
    std::cout << "after" << std::endl;
}

before
//...whatever from the thread code...
Thread 0x00011 is being destroyed.
after