Signal/Slot methods

[Micawber]

Thank you for that insight Marcel. It saved me a lot of digging.

I take it from your explanation of how it works, that it is not possible to have user specified code as a signal method. As in...

class fiddlestix {
Q_OBJECT
 
public signals:
void doThisWhenISignal( int foo );
 
};
 
fiddlestix::doThisWhenISignal( int foo )
{
 
foo += 53;
 
}

class fiddlestix {
Q_OBJECT

public signals:
void doThisWhenISignal( int foo );

};

fiddlestix::doThisWhenISignal( int foo )
{

foo += 53;

}

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In other words, I cannot define a section of code that I wish to be executed every time I emit the signal that does something _before_ Qt starts operating on it?

[marcel]

No, you cannot do that.
At most you can connect another slot to that signal, but before you connect the actual slot.
The first slot will get executed before the second. This is if you want to do something before the second slot is executed.
The connect order dictates the slot execution order for direct connections.

If you want to do something before actually the signal is emitted, you have only one chance: if you emit the signal yourself, i.e. by calling (emit signal). Then you could put some code before the emit statement.

EDIT: when declaring signals, you must not give them a visibility modifier( public, protected, private ). Just signals:. This is opposed to slots, where you always have to specify their visibility.

Regards

[Micawber]

Got it. Thanks Marcel!

Also I take your point re: visibility of signals vs. slots. Good insight.