make fails when installing on Beaglebone Black

[Uwe]

As your Qt version has been built without the designer module you also have to disable "QWT_CONFIG += QwtDesigner" in qwtconfig.pri.

Uwe

[twoten]

Hey that worked great. Make and make install proceeded and finished without problem. But I still don't see any widgets on the palette in Qt Creator. Help - About Plugins doesn't show any Qwt widgets and neither does Tools - Form Editor - About Qt Designer Plugins. Should I create a qwt directory in /qt5/plugins and copy the qwt so file there? Thanks so much for your help!

[Uwe]

When you want to use the Qwt designer plugin you need to build and install a 2nd version of Qwt ( this time with QwtDesigner enabled ), one that is compatible with the creator itself.
Note that the creator is a just a desktop application ( build for some architecture and Qt version ) - and loading the designer plugin is like linking a shared object to the creator at runtime.

Uwe

[twoten]

Well now I'm back where I started. If I enable QwtDesigner in qwtconfig.pri then the make file crashes. If I don't enable it then I end up with an incompatible plugin that won't load. Is there no escape from this infinite loop of frustration?

[Uwe]

Again, you need to have 2 different builds of Qwt: cross compiled for the Beaglebone + another build for the desktop. Those builds have to be done with different Qt versions - the first one is the one that you have cross compiled for the Beaglebone ( here the designer API was disabled as you probably never run the designer/creator on the target ) and the second one is a Qt version that has been compiled for the desktop ( where you run the creator ). The Qt version for the desktop is usually always build with support for designer plugins.

Maybe it helps to read: http://qwt.sourceforge.net/qwtinstall.html#USEPLUGIN

But in your case it should be enough to do the cross compilation with having QwtDesigner disabled. For the Qt creator simply install an official Qwt 6.1 Debiam package, without doing any compilation. This combination should usually match and if you still don't see the Qwt widgets it should be a problem of configuring the Creator ( see link above ).

Then the only problem you need to take care of is, that your build and the Debian package are installed into different directories. Check the options in qwtconfig.pri.

Uwe

[twoten]

Actually I am using Qt Creator on the BBB. Compile time is slow but it runs at an acceptable speed when developing. I tried to set up cross compilation but progress was slow and frustrating. Also my application takes place in the wilderness where even a laptop would be inconvenient.

[twoten]

Okay I solved it. I was installing qt stuff from apt-get in a daze and I ended up with Qt4 Assistant, Designer and Linguist. In Qt Designer the qwt widgets were present and worked fine. I looked at another custom widget which was a blinking led and it would not compile either - it also had the Unknown module(s) in Qt Designer error.

So I did some research and found that I was missing qttools5-dev package. I installed it, and the led widget compiled. I tried compiling qwt and this time it worked. It took like 30 minutes on the BBB but it finished correctly. However make install put the libqwt_designer_plugin.so file in an odd place: /usr/plugins/designer. I tried exporting that as QT_PLUGIN_PATH but it didn't work. I copied the file to a bunch of different places but only after putting it into /usr/lib/arm-linux-gnueabihf/qt5/plugins/designer did it finally work. The qwt plugins appear in Qt Creator and everything works. Whew! Thank you for a great product!