[TUTO] Build Qt to cross compile for arm

citiustech

DO you have any Build steps like QT4.8.5 for QT5.5?

SGaist

That usually depends partly on the device you are targeting.

citiustech

i am cross compiling qt for cubieboard 4.
can you please suggest me ./configure command ?

SGaist

I don't know this board but a quick search returns this blog entry which step 4 is likely what you are looking for to get started.

citiustech

Hello. The above solution is working fine for no-opengl.
once opengl es2 enable for cross compile it gives opengl functionality test failed error. i have copied all the GL/GLES2 file from arm board to ubuntu pc and edit qmake.conf file. but it gives the same error.
how to cross compile qt for arm with opengl. can you please suggest?

SGaist

The headers are not enough, did you also copied the libraries ?

samapollo

Hello,
I know this is a late reply, but hopefully someone is still reading this thread and active. I followed all the steps, and have everything setup. I compiled the file, but when I try and run the make I get an error saying their is no such file or directory of QGLWidget.
I am looking for assistance as to how I can rectify this problem, and finally get my applications building and running. I have included the terminal log below:

/home/sam/Downloads/qt-everywhere-opensource-src-4.8.5/bin/qmake -spec qt-everywhere-opensource-src-4.8.5/mkspecs/qws/linux-arm-gnueabi-g++ CONFIG+=debug -o Makefile ../Qt5.0.2/5.0.2/gcc/examples/opengl/2dpainting/2dpainting.pro
/home/sam/Downloads/gcc-linaro-arm-linux-gnueabihf-4.8-2013.10_linux/bin/arm-linux-gnueabihf-g++ -c -pipe -g -Wall -W -D_REENTRANT -DQT_OPENGL_LIB -DQT_GUI_LIB -DQT_NETWORK_LIB -DQT_CORE_LIB -DQT_SHARED -Iqt-everywhere-opensource-src-4.8.5/mkspecs/qws/linux-arm-gnueabi-g++ -I../Qt5.0.2/5.0.2/gcc/examples/opengl/2dpainting -I/usr/local/Qt-4.8.5-arm/include/QtCore -I/usr/local/Qt-4.8.5-arm/include/QtNetwork -I/usr/local/Qt-4.8.5-arm/include/QtGui -I/usr/local/Qt-4.8.5-arm/include/QtOpenGL -I/usr/local/Qt-4.8.5-arm/include -I. -I../Qt5.0.2/5.0.2/gcc/examples/opengl/2dpainting -I. -o glwidget.o ../Qt5.0.2/5.0.2/gcc/examples/opengl/2dpainting/glwidget.cpp
In file included from ../Qt5.0.2/5.0.2/gcc/examples/opengl/2dpainting/glwidget.cpp:41:0:
../Qt5.0.2/5.0.2/gcc/examples/opengl/2dpainting/glwidget.h:44:21: fatal error: QGLWidget: No such file or directory
#include <QGLWidget>

THANKS!!!

SGaist

Hi and welcome to devnet,

Are you trying to build a Qt 5 example with Qt 4 ?

samapollo

Yes I am, wow I am an idiot.
If I try to use a qt 4 example should it work?

samapollo

So I am using the proper example now, it compiles, but when I run the make It says:

make: Nothing to be done for 'first'.

I have attached the entire command and response below:

sam@sam-VirtualBox:~/Downloads$ "/home/sam/Downloads/qt-everywhere-opensource-src-4.8.5/bin/qmake" '/home/sam/classwizard/classwizard.pro' -r CONFIG+=debug -spec /home/sam/Downloads/qt-everywhere-opensource-src-4.8.5/mkspecs/qws/linux-arm-gnueabi-g++
sam@sam-VirtualBox:~/Downloads$ make
make: Nothing to be done for `first'.

SGaist

Did you cross-compile Qt ? If so did you install it ?

samapollo

I thought I built it for ARM and it would just run on its own.
Do I need Qt installed on my ARM hardware?
When I move the folder to my ARM hardware I get this error when I try to run it:
./classwizard: undefined symbol: _ZN7QWidget8qwsEventEP8QSEvent

SGaist

Looks like you cross-compiled your application with Qt 4 and try to run it against Qt 5.

samapollo

I have Qt 4 on my arm device, but I am still getting the same error. Not sure what to do here?
I have Qt 4 on Raspbian on a Raspberry Pi 3 model B.
Not sure why this error keeps coming up.

SGaist

Because the Qt 4 you have installed with Raspbian is a standard Qt build for ARM not a Qt for embedded device build.

You have have to cross-compile your Qt 4 again without the embedded option.

samapollo

But the Qt I have on my linux where I built the project is for ARM. Its the one for this project.
So should I just use the build from this post on my pi?

SGaist

I didn't say the contrary: both builds are valid. The one you have on your desktop machine is a Qt For Embedded Linux build which uses QWS while on your Raspbian you have a standard as in "desktop standard" build of Qt 4.

It depends on how you want to use your application on your Pi. If its the QWS functionality that you need then you have to install your self-built Qt 4 on the Pi.

samapollo

What if I just created a deb package on my Linux machine, and then used that on the Pi?
Or is it better to just do the custom build? (really dont want to do that painful process)
Is this a guide I can use as a base for this build?:
http://processors.wiki.ti.com/index.php/Building_Qt_with_OpenGL_ES_accelerated_by_SGX

samapollo

So I managed to compile and run a Hello World project. Creating the make and executable on my Linux with this ARM build. Then moving it onto the Pi and running it. But when I try anything more complex I am getting the same error.

SGaist

Again: this is an Qt for Embedded Linux build see the -embedded arm configure option. Thus my question, are you going to use the X Server of your Pi ?

If yes, you have to rebuild Qt without the embedded options but keep the ARM target.

If no, then one basic option is to copy the content of the cross-compiled Qt installation folder over to your Pi at the same place and you should be good to go (you can later remove stuff like the host tools headers etc.)