How to replace the QT installed by apt-get?

korantli

Ubuntu 24.04 laster qt version is 6.4 but deskflow need >=6.7.
I tried the two ways to install qt 6.8

online installer:

The install path is different form the debain pack which is /usr/lib/x86_64-linux-gnu/qt6/. And the contents of them are different.

tree ~/Qt/installerResources -L 1
/home/korantli/Qt/installerResources
├── qt.license.thirdparty
├── qt.qt6.680
├── qt.qt6.680.addons.qtcharts.linux_gcc_64
├── qt.qt6.680.addons.qtmultimedia.linux_gcc_64
├── qt.qt6.680.doc
├── qt.qt6.680.doc.qtcharts
├── qt.qt6.680.doc.qtmultimedia
├── qt.qt6.680.examples
├── qt.qt6.680.examples.qtcharts
├── qt.qt6.680.examples.qtmultimedia
├── qt.qt6.680.linux_gcc_64
├── qt.tools.cmake
├── qt.tools.maintenance
├── qt.tools.ninja
├── qt.tools.qtcreator
├── qt.tools.qtcreator_gui
└── qt.tools.qtdesignstudio

tree /usr/lib/x86_64-linux-gnu/qt6/ -L 1
/usr/lib/x86_64-linux-gnu/qt6/
├── mkspecs
├── plugins
├── qml
└── qt6.conf

source code
build and install, the default path is:/usr/local/Qt-6.8.0/ and contents are:

 tree /usr/local/Qt-6.8.0/ -L 1
/usr/local/Qt-6.8.0/
├── bin
├── doc
├── include
├── lib
├── libexec
├── metatypes
├── mkspecs
├── modules
├── phrasebooks
├── plugins
├── qml
└── translations

However, QT is not recognized by the system as 6.8 by default

......
 deskflow depends on libqt6core6t64 (>= 6.7.2); however:
  Version of libqt6core6t64:amd64 on system is 6.4.2+dfsg-21.1build5.
 deskflow depends on libqt6gui6 (>= 6.7.2); however:
  Package libqt6gui6 is not installed.
  Version of libqt6gui6 on system, provided by libqt6gui6t64:amd64, is 6.4.2+dfsg-21.1build5.
 deskflow depends on libqt6widgets6 (>= 6.7.2); however:
  Package libqt6widgets6 is not installed.
  Version of libqt6widgets6 on system, provided by libqt6widgets6t64:amd64, is 6.4.2+dfsg-21.1build5.

The question is :
How to replace the QT installed by apt-get?

JonB

@korantli
I don't think you should actually "replace" the Qt6 in /usr/lib/... as installed via apt. That would/might lead to confusion as what is there would not correspond to what was fetched by apt (e.g. for update or delete).

I don't know how your

 deskflow depends on libqt6core6t64 (>= 6.7.2); however:
  Version of libqt6core6t64:amd64 on system is 6.4.2+dfsg-21.1build5.

works, but I would expect you to set an option or environment variable to tell deskflow to find Qt6 includes/libraries in wherever you have built Qt (/usr/local/Qt-6.8.0/), or maybe wherever you copy/deploy that to after building if you are supposed to do that. If deskflow has no way of doing this and insists on only using a Qt6 as installed in a "system" region/by apt then that is not very good and you might ask the deskflow people.

SGaist

Hi,

I'd go a step further than @JonB: you just don't.

Trying to replace your system libraries with variants built for development on a larger set of distribution is a no go.

Use the LD_LIBRARY_PATH environment variable to point your application to your custom Qt. Do it in the terminal you use to start that application or in a bash script to start the application.

Do NOT use it to modify which version of Qt is used by your whole system. This will only bring troubles.

korantli

@SGaist

@SGaist said in How to replace the QT installed by apt-get?:

Hi,

I'd go a step further than @JonB: you just don't.

Trying to replace your system libraries with variants built for development on a larger set of distribution is a no go.

Use the LD_LIBRARY_PATH environment variable to point your application to your custom Qt. Do it in the terminal you use to start that application or in a bash script to start the application.

Do NOT use it to modify which version of Qt is used by your whole system. This will only bring troubles.

Got it.