To get the program execution back to main gui ?

[wysota]

I have tried this i mean with qapp->processEvents(); but it showed me error that qapp is not declared in this scope.

You forgot to #include <QApplication>

Thanks now i came to know what actually happens when this function gets called. It checks for any pending event during the execution in do_something(); so that if user clicks any button or does something it will also be executed as:-

Void Square::do_something()
{
  for(i=o;i<100000000;i++) {
  qapp->processEvents();
  ...
  ....}
}

Void Square::do_something()
{
  for(i=o;i<100000000;i++) {
  qapp->processEvents();
  ...
  ....}
}

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Correct.

But sir how can i use qapp created in main.cpp in the outer .cpp class? Those are separate files. I have only included its header in sample.cpp where all slots are implemented. qapp is not even detected in Sample.cpp, giving same error. Or do i have to include any file in Square.cpp?

As you already noticed processEvents is a static method, so you can use it anywhere you want, just include the class' headers.

[Krish]

Hey! Thanks Wysota sir its working now

Ok but i have other question/ doubt. As now i can execute all other slots even if execution is busy, can't i stop the busy execution if takes really long time say more than 10- 20 mins?

Or do i have to use QThreads in which i can in one thread keep GUI alive and in other thread call this busy function. And if it exceeds the waiting limit of user he can stop it with void QThread::terminate (); as we kill the QProcess with kill(); ?

Thanks again in advance.

[wysota]

If you want to have total control, you should use threads or implement your functionality based on events (divide whole process into smaller chunks, etc.).