c++ - Qt Object deleted but signal is not disconnected -

in topic told when qobject deleted active connections deleted. have case below:

work* work = new work();//->work derived qobject  worker* worker  = new worker(work);//->worker derived qthread , has ownership of work  connect(work, signal(percentagecomplete(int)), progressdialog, slot(setvalue(int))); connect(worker, signal(finished()),  worker, slot(deletelater()));  progressdialog->show(); worker->start(); 

in worker's destructor have :

worker::~worker(void){     if(work != nullptr){         work->deletelater();     } } 

i %100 sure work deleted. can see breakpoint. can see qobjects desctructor call.

but how deleted work object still receiving signal "percentage complete". , because deleted ,causing crush.

i want ask why signals not disconnected object deleted?

a second question in worker's destructor work->deletelater(); or delete work; correct?

why dont use disconnect() disconnect connected slots/signals ? can call function in destructor.here have solution similar topic