Qt6 and QGis integration erro of qt5 library

Aman55

**OS : windows 10 64 bit x64

Qt Creator 15.0.0
Based on Qt 6.8.1 (MSVC 2022, x86_64)

Qt compiler : MSVC2022 64 bit

QGIS : Online (OSGeo4W) installer: many version installed by OSGeo4W installer with qgis-qt6-dev**

profile .

QT       += core gui xml

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++17


# Include paths for QGIS and Qt
INCLUDEPATH += C:/OSGeo4W/apps/qgis-qt6-dev/include
# INCLUDEPATH += C:/OSGeo4W/include

# Libraries for QGIS, GDAL, PROJ, and Qt
LIBS += -LC:/OSGeo4W/apps//lib -lqgis_core -lqgis_gui -lqgis_app -lqgis_native -lqgis_analysis -lqgis_server
# LIBS += -LC:/OSGeo4W/lib -lgdal
# LIBS += -LC:/OSGeo4W/lib -lproj

# You can make your code fail to compile if it uses deprecated APIs.
# In order to do so, uncomment the following line.
#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0

SOURCES += \
    main.cpp \
    mainwindow.cpp

HEADERS += \
    mainwindow.h

FORMS += \
    mainwindow.ui

# Default rules for deployment.
qnx: target.path = /tmp/$${TARGET}/bin
else: unix:!android: target.path = /opt/$${TARGET}/bin
!isEmpty(target.path): INSTALLS += target

main.cpp file

#include "mainwindow.h"

#include <QApplication>
#include <qgsapplication.h>
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    w.show();
    return a.exec();
}

Issue:- Giving error of qt5 dll file why? qt5xml, qt5svg, qt5sql.dll etc.

Screenshot (9).png

Christian Ehrlicher

@Aman55 said in Qt6 and QGis integration erro of qt5 library:

Issue:- Giving error of qt5 dll file why? qt5xml, qt5svg, qt5sql.dll etc.

So you somehow loaded the Qt5 qgis stuff. You can not mix it. It's up to you to make sure to use the correct ones - what should we do here?
You can check which dlls are loaded from which dependency with e.g. Dependencies