Qt5.12.3: C++ signal -> QML slot

[Melle_87]

@LeLev :
Okay. Now I created a repo on github.

link to example

Now this example is really stripped down to a minimum. Please don't ask for the sense of this project now. Because now it does not make sense anymore. But it demonstrates the error.

[J.Hilk]

@Melle_87 thanks,

I assume, in the example for your case, the background does not turn red ?
because it does for me, out of the box

Qt 5.12.2
MacOS

---

edit:
same on windows, 5.12.2 as well I don't have a desktop 5.12.3 version. background turns red, either way, with or without debugger attached.

[Melle_87]

@J.Hilk: Yes.
When I start the application out of Qt Creator via "Start debugging" the rectangle keeps blue and I get the error "ReferenceError: name is not defined".
If I start the application via "Run" the rectangle gets red and I get no errors.

As I mentioned before:
I am using Qt5.12.3. (Before I used Qt5.9.)
I am developing on Ubuntu and crosscompiling for Raspberry Pi 3.

Maybe in your case it is working because of your Qt5.12.2 version?

[J.Hilk]

@Melle_87 said in Qt5.12.3: C++ signal -> QML slot:

Maybe in your case it is working because of your Qt5.12.2 version?

maybe,
what are your debug settings, do you have qml debugging and profiling enabled ? do you use the QtQuickCompiler?

[Melle_87]

@J.Hilk: Yes.
Qml debugging is enabled. At application start I get: QML debugging is enabled. Only use this in a safe environment.
As debugger I am using: ~/raspi/tools/arm-bcm2708/arm-rpi-4.9.3-linux-gnueabihf/bin/arm-linux-gnueabihf-gdb

[KroMignon]

@Melle_87 said in Qt5.12.3: C++ signal -> QML slot:

Maybe in your case it is working because of your Qt5.12.2 version?

I've got same issue here with Windows XP7 64 and Qt5.12.3 32bit/MSVC2017:

• when starting in debug (F5) the window stays blue,
• when starting with "run" (Ctrl+R) the windows becomes red!

[J.Hilk]

Well, I went and installed 5.12.3

And loe and behold, the background stays blue. And the QML error appears in the console.

since it works with 5.12.2 I would say this is a bug.

You should open that bug report you mentioned. The minimal example will help speed that one up as well!

You should post a link to the ticket, when you have. So others can find and follow it as well!

[Melle_87]

@J.Hilk:
I created a bug report.
link to bug report

But nevertheless. If someone already has a solution or workaround for this problem I would be glad to know.

[KroMignon]

@Melle_87 Very strange, I've cleaned up a little bit the project:

in pro file

...
#QT += core gui serialport serialbus network sql qml quick widgets dbus multimedia multimediawidgets printsupport
QT += core gui qml quick widgets printsupport
...

in Main.qml

import QtQuick 2.6
import QtQuick.Window 2.3
import QtQuick.Controls 1.4
import "."

...

Remove all build direction, rebuild all and now window is always red!?! in Release and Debug.

[J.Hilk]

@KroMignon
you must have done more, as simply changing the pro file to only include those, still results in a blue background for me

[KroMignon]

@J.Hilk No, I've recheck with git-diff

[Melle_87]

@KroMignon: I also can not confirm this. I changed .pro and Main.qml. But in Debug the window still stays blue and in release it gets red.

[KroMignon]

@Melle_87 @J-Hilk it seems issue has already been reported and fixed in next release 5.12.4
QTBUG-75393

[Melle_87]

@KroMignon: Yes. I saw this also. But then I have to go back to 5.12.2. Because I can not wait for Qt5.12.4.

[KroMignon]

@Melle_87 According to Qt 5.12 release plan, Qt 5.12.4 should be release @ 11.06.2019

[Melle_87]

@KroMignon: Okay. Thanks for that info.