c++ - future get is terminating the proggram -

i running process asynchronously using qevent, after process complete setting promise , trying using future function.

but not working asynchronously process, it's working in synchronous process

may know wrong doing.

code:

win::win(qobject *parent) :     mycustomwidget(parent) {     qdebug()<<execute().get();  } std::future<int> win::execute() {     auto promise = std::make_shared<std::promise<int>>();     auto temp = [=]     {         ///process         qdebug()<<"done";         promise->set_value(100);      };      qapplication::postevent(this,new mycustomevent(temp));     ////qapplication::processevents()  without line not working may know reason    //// without line , without future working     return promise->get_future(); }