Detect thread end

Question

How can I detect when a thread was ended (in a platform independent way)? I have to store copies of objects for every thread and I want to know when I can dispose or redistr

Answer 1

With multiple threads, in order to detect any one of them was ended, you need:

A shared condition_variable for notification, a shared mutex to lock, and shared variables for conditions of all threads.

void call_me_at_the_end_of_a_thread(int index_of_thread){
    std::unique_lock l(the_global_mutex);
    array_of_bools[index_of_thread] = true;
    num_of_dead_threads++; // global integer only for the convenience of checking before wait
    std::notify_all_at_thread_exit(the_global_condition_variable, std::move(l));
}

You may use an array of bool or vector for checking which threads was ended. You may prefer notify_all to notify_all_at_thread_exit if you don't care about the timing of notifying after current thread has finished "completely".

void call_me_to_detect_thread_was_ended(void){
    static int copy_of_num_of_dead_threads;
    std::unique_lock l(the_global_mutex);
    while(num_of_dead_threads==copy_of_num_of_dead_threads)
        the_global_condition_variable.wait(l);
    std::cout<

num_of_dead_threads is only for simplicity. Check the array_of_bools to find out which threads have already finished.