JayTwoLab / UseOldQt5inQt6

Use old Qt5 in Qt6 :kr: Qt6에서 구형 Qt5 사용하기

UseOldQt5inQt6

Use Old Qt5 in Qt6

1️⃣ Set qmake(.pro) or cmake(CMakeList.txt).

• For qmake(.pro)

QT += core5compat

• For cmake(CMakeList.txt)

PUBLIC_LIBRARIES
Qt::Core5Compat

2️⃣ Check old Qt5 class.

Qt 5 Class	Qt 6 Replacement
QLinkedList	std::list *
QRegExp	QRegularExpression
QStringRef	QStringView
QXmlSimpleReader	QXmlStreamReader
QTextCodec	QStringConverter
QTextEncoder	QStringEncoder
QTextDecoder	QStringDecoder

• If you are planning a long-term upgrade, Upgrade old class to a new version of new class.

Code

• UseOldQt5inQt6.pro

# UseOldQt5inQt6.pro

message( 'Qt major version : ' $$QT_MAJOR_VERSION ) # test in Qt6.

##################################
# TODO: Append for old Qt5 code.
QT += core5compat
##################################

QT -= gui

CONFIG += c++11
CONFIG += console
CONFIG -= app_bundle

# 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

# 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

// main.cpp

#include <QtGlobal>
#include <QString>
#include <QDebug>
#include <QCoreApplication>
#include <QStringView> //  Qt 5.10 or higher version

//----------------------
// #include <QtCore5Compat> // you may use this header.
#include <QtCore5Compat/QStringRef> // QStringRef : Qt4.3 ~ Qt5
//----------------------

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);

#if QT_VERSION_MAJOR == 6
    // custom code for Qt 6 or higer version
   qDebug() << "Qt version is six.";
#endif

#if QT_VERSION_MAJOR == 5
    // custom code for Qt 5
   qDebug() << "Qt version is five.";
#endif

#if QT_VERSION_MAJOR == 4
   // ? Are you still in use?
#endif

    QString qstr("Hello, Qt5 in Qt6.");

    // Qt5 class ( QStringRef )
    QStringRef sref( &qstr );
    qDebug() << "QStringRef" << sref;

    // Qt6 class ( QStringView )
    QStringView sv( qstr );
    qDebug() << "QStringView" << sv;

    return 0; // return a.exec();
}

🇰🇷 Qt6에서 구형 Qt5 사용하기

• (Korean Blog) https://j2doll.tistory.com/671