Hi Willem,
> On Jan 18, 2020, at 3:48 AM, Willem Ferguson
> <[email protected]> wrote:
>
> Following excellent review of a recent PR, I was asked to update the
> conventional string-based Qt connections to the new-style Qt connections.
> (https://wiki.qt.io/New_Signal_Slot_Syntax
> <https://wiki.qt.io/New_Signal_Slot_Syntax>) The old style is:
>
> connect(
> sender, SIGNAL( valueChanged( QString, QString ) ),
> receiver, SLOT( updateValue( QString ) )
> );
> My old-style connection is:
>
> connect(ui.timeDiffEdit, SIGNAL(timeChanged(const QTime)), this,
> SLOT(timeDiffEditChanged()));
>
> For the new style the specification in the Qt documentation is:
>
> connect(
> sender, &Sender::valueChanged,
> receiver, &Receiver::updateValue
> );
So as you see here, the documentation wants you to use the function address as
argument...
> My formulation, reflecting my strong deficiencies in Qt coding but following
> the above, for the new connection is:
>
> connect(this, ui.timeDiffEdit->timeChanged(ui.timeDiffEdit->time()),
> this, this->timeDiffEditChanged());
>
> The second parameter needs to be a pointer, for which I used ui.timeDiffEdit.
> The timeChanged() signal needs a QTime value, so I provided that with
> ui.timeDeffEdit->time(), the actual amount of time by which the timeDiffEdit
> has been changed.
> The last parameter also needs an address, provided by
> this->timeDiffEditChanged() is the response to the signal from
> timeDiffEdit->timeChanged(). It is a void function and the source of build
> problems. The compiler generates an error:
>
> /home/willem/src/subsurface/desktop-widgets/importgps.cpp:30:104: error:
> invalid use of void expression
> connect(this, ui.timeDiffEdit->timeChanged(ui.timeDiffEdit->time()), this,
> this->timeDiffEditChanged());
>
> ^
>
> Obviously, accessing the pointer this->timeDiffEditChanged() should not
> return a void value. I have no idea of how to respond to this error. Any
> suggestions are very welcome. For completeness I attach the code for the full
> object to this email.
>
>
How about
connect(this, &QTimeEdit::timeChanged, this, &ImportGPS::timeDiffEditChanged);
That seems like it would follow the syntax suggested above, right?
/D
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