[TUTO] Build Qt to cross compile for arm

SGaist · wrote on 24 Jun 2016, 13:53

Hi and welcome to devnet,

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

samapollo · wrote on 24 Jun 2016, 14:55

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

samapollo · wrote on 24 Jun 2016, 15:07

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 · wrote on 24 Jun 2016, 20:07

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

samapollo · wrote on 27 Jun 2016, 08:14

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 · wrote on 27 Jun 2016, 09:09

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

samapollo · wrote on 27 Jun 2016, 11:40

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 · wrote on 27 Jun 2016, 11:46

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 · wrote on 27 Jun 2016, 12:12

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 · wrote on 27 Jun 2016, 12:20

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 · wrote on 27 Jun 2016, 12:30

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 · wrote on 27 Jun 2016, 14:50

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 · wrote on 27 Jun 2016, 16:13

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.)

samapollo · wrote on 14 Jul 2016, 11:22

How can I do this compilation with opengl?

SGaist · wrote on 14 Jul 2016, 20:58

Which version of Qt are you currently using ?

HafsaElif · wrote on 17 Jul 2019, 06:49

Execute this command to install Qt in the /usr/local/Qt-4.8.5-arm/ directory : ./configure -opensource -confirm-license -prefix /usr/local/Qt-4.8.5-arm -embedded arm -little-endian -no-pch -xplatform qws/linux-arm-gnueabi-g++

In this step Did you create /usr/local/Qt-4.8.5-arm/ directory ? or Did created by qt creator when installitaion?

Asha · wrote on 12 Sept 2019, 10:28

This post is deleted!

Asha · 12 Sept 2019, 10:57

Hi,

I am not understood that fourth step,

Go to /home/<yourUserName>/
Execute this command to install Qt in the /usr/local/Qt-4.8.5-arm/ directory : ./configure -opensource -confirm-license -prefix /usr/local/Qt-4.8.5-arm -embedded arm -little-endian -no-pch -xplatform qws/linux-arm-gnueabi-g++
qt-everywhere-opensource-src-4.8.5/

why beacuse,when i go /home/<username> there is no such file called (this present in installQt directory) and in /usr/local also not present the Qt-4.8.5

anyone help how to processed next..
thankyou

jsulm · A Asha 12 Sept 2019, 10:53

@asha You should not copy the steps exactly, you have to adapt them to your environment:
Go to /home/<yourUserName>/ - this means go to your home directory
Qt-4.8.5 - change that to the Qt version you want to compile.

Asha · 12 Sept 2019, 12:44

Sir,

I have uninstalled everything(which means cross compiler and my first qt version)

now i followed the steps,as said in above..

so now I am not getting where to execute.

can I execute where i am getting the configure file.