Need help releasing a QT binary that uses QML with C++.

BlackApples · 1 Aug 2022, 10:49

Hello, I wanted a C++ class that talks with QML.
In my .pro file. I have the following declaration:

CONFIG += qmltypes
QML_IMPORT_NAME = banana.boutput
QML_IMPORT_MAJOR_VERSION = 1
...
RESOURCES += qml.qrc

# Additional import path used to resolve QML modules in Qt Creator's code model
QML_IMPORT_PATH =

# Additional import path used to resolve QML modules just for Qt Quick Designer
QML_DESIGNER_IMPORT_PATH =

The main.cpp consists of:

qDebug("Welcome...\n");
QGuiApplication app(argc, argv);
QQmlApplicationEngine engine;

qmlRegisterType<Banana>("banana.boutput",1,0,"BOutput");

const QUrl url(QStringLiteral("qrc:/main.qml"));
QObject::connect(&engine, &QQmlApplicationEngine::objectCreated,
                 &app, [url](QObject *obj, const QUrl &objUrl) {
    if (!obj && url == objUrl)
        QCoreApplication::exit(-1);
}, Qt::QueuedConnection);
engine.load(url);

return app.exec();

In the qml.qrc -> main.qml I have:

import QtQuick
import QtQuick.Window
import QtQuick.Controls
import banana.boutput 1.0

Window {
    width: 100
    height: 100
    visible: true
    title: qsTr("Hello World")
    id: aWindow
    objectName: "awindows"
    color: "black"

BOutput {
id: bananachild
}

ComboBox {
        id: selectbananachild
        objectName: "bananaChildSelector"
        visible: true
        width: parent.width
        onCurrentIndexChanged: bananachild.onSelected(selectbananachild.currentIndex,selectbananachild.textAt(selectbananachild.currentIndex))
    }

    Component.onCompleted: {
        bananachild.passParent(aWindow);
        aWindow.width = selectbananachild.width
    }

}

And this all works. I hit compile and run inside QTCreator and it works fine. The QML and C++ are talking and all is good. Now I want to release it, and make it standalone.

I switch configuration to release and build. I copy the .exe over to a new folder.

I then open a PowerShell terminal and navigate to the correct folder containing windeployqt.exe. In my case, it is Qt\6.2.2\msvc2019_64\bin.

I run .\windeployqt.exe locationOfBuildDirectory

When launching the released binary (.exe), it does nothing. Not even the "Welcome..." from main.cpp is outputted to the terminal. When using the tool dependency walker I get the following error:
?qml_register_types_banana_boutput@@YAXXZ

It runs and executes fine in QTCreator, what am I doing wrong?

BlackApples · wrote on 2 Aug 2022, 14:34

As it turns out, there was no issue. The application was doing exactly what it was told to do. The QML CPP implementation was looking for a JSON file. When in an event the application could not find the file, it should print something to console and exit. In this case, the pathing of the file was incorrect so it just exited without saying anything in the console. It has been resolved.

Thank you all for your help.

mrjj · wrote on 1 Aug 2022, 10:49

@BlackApples said in Need help releasing a QT binary that uses QML with C++.:

windeployqt.exe

Hi
It should have picked up you are using QML

you can try with
--qmldir pathtowherefilesare

BlackApples · 1 Aug 2022, 11:04

It should be noted there is no "boutput.qml" file anywhere. It is all declared in C++ as a QML_ELEMENT in the header file (.h).

I have tried that command. No success. The qmldir was pointed to the source directory

mrjj · 8 Jan 2022, 11:05

@BlackApples
Did it copy any Qt dlls to the folder ?
the qmlimportscanner should look at the files but it sounds like some goes wrong.

so you ran it like

windeployqt --qmldir c:\myApp\sources c:\build-myApp\myApp.exe    (-ish paths different)

BlackApples · 1 Aug 2022, 11:23

@mrjj

windeployqt --qmldir c:\myApp\sources c:\build-myApp\myApp.exe (-ish paths different)

Yes, this is how I ran it.

I did not copy any additional Qt DLLs to the release folder. I assumed windeployqt would copy all the necessary DLLs I require.

BlackApples · wrote on 1 Aug 2022, 11:20

The file structure of the source folder is the following:

bananaproject.pro
bananaproject.user.*
main.cpp
main.qml
main.qrc
banana.h
banana.cpp

mrjj · wrote on 1 Aug 2022, 11:23

@BlackApples
Hi
well, I have seen posts that sometimes windeployqt don't get it all.
But from your answer, it does copy the normal Qt DLLs but not the QML ones ?
(any DLLs with QML in name ?)

Also the main.qml is added to the resource so its compiled in, right ?

I do wonder why it does not complain about missing DLLS when you click exe but just shows nothing.

Do you run the .exe on same PC or "clean" one ?

J.Hilk · wrote on 1 Aug 2022, 11:24

@BlackApples first of, I would suggest executing the qtenv2.bat inside the folder, that also contains windeployqt

.\windeployqt.exe locationOfBuildDirectory

that it wrong, instead of BuildDirectory, explicitly name the path and executable name , including extension.

do not forget to add -qmldir, like @mrjj said

and lastly, make sure, you're using the environment & windeployqt of the kit you used to compile/generate your executable

BlackApples · 1 Aug 2022, 11:59

I have opened up a new PowerShell terminal. I have run qtenv2.bat and vcvarsall.bat amd64.
I then run the following command in the Qt\6.2.2\msvc2019_64\bin:

.\windeployqt --qmldir "c:\myApp\bananaproject" "c:\build-myApp\bananaproject.exe"

Then from the same terminal. I navigate to c:\build-myApp\. I run .\bananaproject.exe.

Same error. Nothing in the terminal. Application exits immediately.

J.Hilk · wrote on 1 Aug 2022, 11:59

@BlackApples ok, as a test, give the qml path of the kit, instead of your project

--qmldir C:\Qt\Qt6.2.2\ msvc2019_64\qml

that will pull in and copy everything QML related. Its a brute force test, see if your app now starts.

BlackApples · 1 Aug 2022, 12:20

Command executed:
.\windeployqt.exe -qmldir "C:\Qt\6.2.2\msvc2019_64\qml" "c:\build-myApp\bananaproject.exe"

Result when running .\bananaproject.exe:
Same error. Nothing in the terminal.

J.Hilk · wrote on 1 Aug 2022, 12:20

@BlackApples interesting.

you said, the path is similar to what you posted, are there any special characters and or spaces in the path?

can you show the folder after the tool ran on it?

did you run the tool with --force argument? in cause there are residual files from a potentially wrong windployqt tool ?

what additional information do you get, when you run the tool vis a verbose level ?
--verbose <level> Verbose level (0-2).

BlackApples · 2 Aug 2022, 05:27

I have not run with the windeployqt.exe with the --force argument. Should I try it?

Build directory:

D3Dcompiler_47.dll
Qt
Qt5Compat
Qt63DAnimation.dll
Qt63DCore.dll
Qt63DExtras.dll
Qt63DInput.dll
Qt63DLogic.dll
Qt63DQuickScene2D.dll
Qt63DRender.dll
Qt6Concurrent.dll
Qt6Core.dll
Qt6Gui.dll
Qt6LabsFolderListModel.dll
Qt6Multimedia.dll
Qt6MultimediaQuick.dl
Qt6Network.dll
Qt6OpenGL.dll
Qt6Qml.dll
Qt6QmlLocalStorage.dll
Qt6QmlModels.dll
Qt6QmlWorkerScript.dll
Qt6QmlXmlListModel.dll
Qt6Quick.dll
Qt6Quick3D.dll
Qt6Quick3DAssetImport.dll
Qt6Quick3DAssetUtils.dll
Qt6Quick3DEffects.dll
Qt6Quick3DHelpers.dll
Qt6Quick3DParticles.dll
Qt6Quick3DRuntimeRender.dll
Qt6Quick3DUtils.dll
Qt6QuickControls2.dll
Qt6QuickControls2Impl.dll
Qt6QuickDialogs2.dll
Qt6QuickDialogs2QuickImpl.dll
Qt6QuickDialogs2Utils.dll
Qt6QuickLayouts.dll
Qt6QuickParticles.dll
Qt6QuickShapes.dll
Qt6QuickTemplates2.dll
Qt6QuickTest.dll
Qt6QuickTimeline.dll
Qt6ShaderTools.dll
Qt6Sql.dll
Qt6StateMachine.dll
Qt6StateMachineQml.dll
Qt6Svg.dll
Qt6Test.dll
Qt6VirtualKeyboard.dll
QtMultimedia
QtQml
QtQuick
QtQuick3D
QtTest
bananaproject.exe
geometryloaders
iconengines
imageformats
networkinformation
opengl32sw.dll
platforminputcontexts
platforms
qmltooling
renderers
renderplugins
sceneparsers
sqldrivers
tls
translations
vc_redist.x64.exe
virtualkeyboard

I'm not sure what I'm doing wrong. I suspect it might be due to the application not being able to find the C++ implementation of the QML type BOutput. But I'm not an expert on this. I'm not too sure what it is doing. It does work and runs in QTCreator.

The --verbose 2. There is no mention of an error. Additionally, there is no mention of BOutput - the CPP QML implementation.

Command ran:
.\windeployqt.exe --qmldir "c:\myApp\bananaproject" "c:\build-myApp\bananaproject.exe" --verbose 2

fcarney · wrote on 1 Aug 2022, 21:57

I thought Qt creates a shell for each kit that gets installed. Then you open that shell to run commands related to that kit. I usually open the shell for the kit (it is in the start menu somewhere) then cd to the directory where I want to run the deploy program. The paths should be all correct for this.

J.Hilk · wrote on 2 Aug 2022, 05:27

@BlackApples ok, Qt6, haven't really used that yet, at least not deployed.

From what I know, a Qt5 Application would miss, the bearer folder, QtQuick.2(probably no longer needed for qt6), scenegraph, styles

Like I said, not sure if a Qt6 application still requires those folders/dlls

I have not run with the windeployqt.exe with the --force argument. Should I try it

yes, in case you once used the wrong tool, from the wrong kit, the dlls won't be overwritten, since they are already "deployed"

BlackApples · wrote on 2 Aug 2022, 14:34

As it turns out, there was no issue. The application was doing exactly what it was told to do. The QML CPP implementation was looking for a JSON file. When in an event the application could not find the file, it should print something to console and exit. In this case, the pathing of the file was incorrect so it just exited without saying anything in the console. It has been resolved.

Thank you all for your help.