Emit one signal from multiple classes

[Ishmael]

According to the documentation on signals and slots: "Only the class that defines a signal and its subclasses can emit the signal." Is there an elegant way to circumvent this restriction? I would like to be able to emit a signal from multiple classes. Thanks for your help!

[Lykurg]

Well you can define the same signal in all your classes or create a minimal class defining the signal and use it as a "global" base class. (I am not sure why someone want to do so, so can you tell us what you are trying.)

Or if I don't get you right and you want emit a signal of a foreign class, then you have to create a public function which emits the signal, so that you can call that function from your other classes. (?)

[Ishmael]

Those are good suggestions, thanks! Just to clarify, the situation I have is this: I have a simple GUI (QMainWindow) as well as a class that reads from a serial port (I'm using qextserialport, which has its own thread). When certain bytes are read from the serial port, I would like to emit a signal that the main GUI responds to. The same signal can be emitted from within the GUI too (which is where the signal is defined), hence the desire to have a 'global' signalling mechanism. For now, I've been able to work around the issue by simply avoiding the signal/slot mechanism in my serial port class and calling the required functions in my GUI class directly instead of emitting a signal.

[squidge]

Your serial thread is calling functions in your gui class directly?

But it would seem that you would be better off using an event. They can be generated and send from anywhere.

[ChrisW67]

For now, I've been able to work around the issue by simply avoiding the signal/slot mechanism in my serial port class and calling the required functions in my GUI class directly instead of emitting a signal.

I don't see what needs a work-around here. Your GUI class defines a signal that you connect to a slot that is also defined in the GUI class (although you could call it directly from here). The serial port management class also defines a signal that you connect to the GUI object's slot. Whether you name the signals identically is irrelevant.