How to completely un-install Qt



  • I'm running CentOS 6. When I installed the OS, it came with what looked like Qt version 3.3.8b. A run or two of "yum update qt" resulted in version 4.6.2. Then when I installed qt-creator I got Qt version 5.5.1.

    There appear to be many artifacts of earlier versions on my machine. For example, when I built a simple app in one of the Qt tutorials that just displays the Qt version number, it came up with 3.3.8b.

    What I would like to do is completely remove all traces of Qt and start over with a fresh install, so that I know what I have. What is the correct way (among all the incorrect ways) to do that? Do I just say "yum remove qt-creator" followed by "yum remove qt" or is there more to it than that?

    Thanks...

    Eric


  • Moderators

    How did you install QtCreator? Using CentOS repository, offline installer, online installer?
    Did your really install Qt 5.5.1? If so then just check whether you have a Kit in QtCreator configured to use that Qt version.
    There is no need to uninstall the old Qt, it quite likely that it is needed by some software. Just install Qt 5 (5.6 is the current version) and use it in QtCreator.



  • @jsulm >> How did you install QtCreator?

    I became root and said "yum install qt-creator" and sat back while it did it's thing.

    @jsulm >> Did your really install Qt 5.5.1?

    That appears to be what "yum install qt-creator" installed. Help->About Qt Creator reads:

    Qt Creator 3.0.1
    Based on Qt 5.5.1 (GCC 4.4.7 20120313 (Red Hat 4.4.7-4), 64 bit)

    Built on Mar 6 2014 at 04:20:13

    I realize this isn't the latest and greatest (of either Qt Creator or Qt itself) but I'm trying to stick with what the distro's installer gives me, and we all know CentOS isn't exactly the bleeding edge..

    @jsulm >> There is no need to uninstall the old Qt, it quite likely
    @jsulm >> that it is needed by some software. Just install Qt 5
    @jsulm >> (5.6 is the current version) and use it in QtCreator.

    OK. I'm just a bit concerned that I'll be referencing the wrong Qt tree. I've already run into that with a tutorial demo program that just displays the version; it came up with version 3.3.8b until I changed the PATH to point to qt5 then it came up with version 5.5.1.

    If it's OK to leave all the old stuff in place, so be it.

    Thanks...

    Eric


  • Moderators

    @eric-rkt said:

    I became root and said "yum install qt-creator" and sat back while it did it's thing.

    This installs the Qt Creator IDE. It doesn't install the Qt libraries (unless your distro marked Qt dev files as a dependency of Qt Creator).

    The distinction is important, because the IDE is a standalone program. You can install many different versions of the library, and use them all from one copy of the IDE.

    Help->About Qt Creator reads:

    Qt Creator 3.0.1
    Based on Qt 5.5.1 (GCC 4.4.7 20120313 (Red Hat 4.4.7-4), 64 bit)

    This means Qt Creator was build using Qt 5.5.1. It doesn't necessarily mean that Qt 5.5.1 was installed on your system.

    OK. I'm just a bit concerned that I'll be referencing the wrong Qt tree. I've already run into that with a tutorial demo program that just displays the version;

    When you create a project in Qt Creator, you are given the option of which version of Qt to use.

    To run your program outside of Qt Creator, see http://www.tripleboot.org/?p=138

    it came up with version 3.3.8b until I changed the PATH to point to qt5 then it came up with version 5.5.1.

    OK, it looks like Qt 5.5.1 was indeed installed in your case.

    If it's OK to leave all the old stuff in place, so be it.

    It is generally safe to have multiple versions of Qt on the same machine. Note that Qt 3.3.8 is ancient and support for it ended long ago though.



  • Thanks for all your help on this. I'm going to mark it "solved" for now while I digest all of your advice. I'll be back if I run into any more issues.

    Eric


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