qmake: could not find a Qt installation of ''

Question

I have a software in ubuntu that requires me to run qmake to generate the Makefile.

However, running qmake gives back this error,

qmake: could not find a Qt installation of ''

I have installed what I thought to be the required packages using,

sudo apt-get install qt4-qmake
sudo apt-get install qt5-qmake

But the error didn't go away.

Any help on this would be gladly appreciated!

Solution 1

sudo apt-get install qt5-default works for me.

$ aptitude show qt5-default

tells that

This package sets Qt 5 to be the default Qt version to be used when using development binaries like qmake. It provides a default configuration for qtchooser, but does not prevent alternative Qt installations from being used.

Solution 2

You could check path to qmake using which qmake.

Consider install qt4-default or qt5-default depends what version of qt you want use.

You could also use qtchooser - a wrapper used to select between Qt development binary versions.

Solution 3

For others in my situation, the solution was:

qmake -qt=qt5

This was on Ubuntu 14.04 after install qt5-qmake. qmake was a symlink to qtchooser which takes the -qt argument.

Solution 4

As Debian Qt's maintainer please allow me to suggest you to not use qtx-default. Please read qtchooser's man page, the solution is described there. If you are interested in packaging an app you can also take a look at this blog post I made explaining how to do it

# method 1
QT_SELECT=qt5 qmake

# method 2:
export QT_SELECT=qt5
qmake
... more qt commands here

# method 3:
make -qt5

To use Qt 4, just replace the qt5 with qt4

Update 20210202: starting from Debian 11 (bullseye) the packages qtx-default do not longer exist. Same goes for Ubuntu, but I don't know in which specific version. If you know of a package that still has the dependency (mostly non-Debian official packages) please file a bug. Same goes for Wiki pages, etc.

Solution 5

I had this problem building jasmine-headless-webkit Ruby gem. Despite having qt4 installed, qmake (a symlink to qtchooser) insisted it didn't know about a QT installation. OTOH, it was able to list qt4 when asked directly.

This made everything better:

export QT_SELECT=qt4

qtchooser then knew to use qmake-qt4, and so on.

View more solutions

Comments

[sashoalm]

Try running sudo apt-get install qtcreator. It installs the full Qt SDK + an IDE. It should add everything you need.

[IssamLaradji]

Hi @sashoalm, thanks a lot, seems I had other packages missing. Now its working :D

[Scone]

This is not a good solution as it will install many potentially unneeded packages.

[IssamLaradji]

Hi @Warthel4578, thanks, your answer helped me indirectly, since I installed qt4-qmake, I should have invoked 'qt4-qmake' instead of 'qmake' (I found both of them in the directory path). Now its working :)

[user35443]

Can you please decribe your solution more?

[thias]

the accepted answer is not an answer at all. This one should be the accepted answer.

[Scone]

Thanks Warthel this helped me discover why my qmake wasn't working. qmake on Ubuntu 14.04 was symlinked to qtchooser

[Alex Ryan]

Perfect! I had the same problem when trying to install qBittorrent, and mine was solved with export QT_QMAKE=/usr/bin. Never know when those environment variables will come back to bite ya!

[Robie Basak]

Can you explain why we shouldn't use qtx-default, please? The qtchooser manpage helps me understand what is going on, but I don't see why having a package supply a default is a problem.

[Salil]

Following sets up the complete qt5 development installation for me: apt-get install qt5base-dev qtdeclarative5-dev qt5-qmake qt5-default qttools5-dev-tools And then check using: qtchooser -print-env

[Xofo]

It would be nice if qmake-qtX was bundled under the relevant qt version. Pulling in these pieces is bit cumbersome.

[Martin Zeitler]

how about to add a comment, why this answer was down-voted? failing to understand or to apply the solution does not exactly qualify as a valid reason ...while I'm pretty certain it works, because I have it working just like that.

[sameers]

I got to this SO answer, then found, based on the next error (no qtwebkit installation found) that I also had to run apt-get install qt5-default libqt5webkit5-dev gstreamer1.0-plugins-base gstreamer1.0-tools gstreamer1.0-x as described on the Thoughtbot Github wiki page

[lisandro]

@RobieBasak sure thing: let's say you install qt5-default. Then you run a qt4 application which calls qdbus. You get qt5's qdbus, which should work but it's not warranted to do it.

[Robie Basak]

Surely that's a bug in how the qt4 application calls qdbus or in the environment the qt4 application was run in, rather than my choice to want qt5 by default from my CLI?

[lisandro]

First thing: maybe qdbus was a bad example. Let's say upstream decided to not rename Qt's underlying tools with the 4 to 5 change. So it is not possible to know beforehand which version the app will run except you have qtchooser in the middle. But qtchooser, even if it's a nice attempt, does fall short in a number of places, at least in the distro world. Ideally each app should be either be recalled after the major version or compatibility should be retained.

[Tom Saleeba]

This is a great solution when you just want qmake and don't want a full qt environment.

[While-E]

Throwing the upvote your way because I'm not an apt-get tard, and I actually build from source, and this symlink answer was the closes to getting me on track because I forgot I had aliased my 'qmake'. Thanks.

[Akito]

Of all the answers this is actually the only one that remotely worked. Except I needed to use /usr/lib/x86_64-linux-gnu/qt5/bin/qmake.