Qwt: Is it possible to perform GUI operations from a separate QProcess?

[seanj]

Don't know where you read this, but it is wrong. Signals can be emitted from any method. How they get handled depends on what type of signal/slot connection was made. See the documentation for QObject::connect().



You realize you have set up an infinite loop here, right? You have connected the plotUpdated() signal to the onPlotUpdated() slot, and in that slot you emit the plotUpdated() signal, which calls the slot, which emits the signal, which calls the slot...



I don't have any idea what you are trying to do with this QTimer. And if all you want to do is call the onPlotUpdated slot, then make that the slot connected to the timer's timeout signal. No need to add a special slot that simply emits the plotUpdated signal.

1. I do not remember exactly, but I thought I read it in a Qt forum, I cannot find it anymore.

2. I am aware of the infinite loop, my plan was to just add a counter variable and only emit the signal when the count is below a certain value.

3. The sole reason I used a single shot timer is just so I could enter the event loop to emit a signal, but I now know that is not necessary.

Thank you very much for the guidance, I really appreciate it.

[d_stranz]

Signals can be emitted from any method.

A small correction - the method has to be a member of a class derived from QObject that contains the Q_OBJECT macro in its class definition, and the signal function itself must be declared as a signal in that class. Otherwise the MOC compiler won't generate the boilerplate code that defines the signal and integrates it into signal / slot connections. Typically signals are private or protected class methods that can't be called except from within their own classes.