Multiple Widgets of same class, one single thread for computation - adressing problem

[jacek]

Having e.g. 20 widgets and 20 data-sources I have to send 400 signals, that is not efficient.

Then maybe you need a DataSource object that will emit appropriate signal?

Another alternative is to use dynamic signals, but it's a bit hackish.
http://doc.trolltech.com/qq/qq16-dynamicqobject.html

Is there any sample for custom events? I'm using QT4.

All you need it to is subclass QEvent and reimplement QObject::customEvent() in receiver. To dispatch events you can use QCoreApplication::postEvent().

In Qt 4, custom events are created by subclassing QEvent and reimplementing the type() function to return a value in the range allocated for user events. Event-specific data can be stored in a way that is appropriate for your application. Custom events are still delivered to each object's customEvent() handler function, but as QEvent objects rather than as deprecated QCustomEvent objects.