Qt X Compiling

Intro

It is a quite common case when developing a QT based application for an Embedded Linux system is carried out on an host machine with a different architecture.

This is a brief manual that shows:

• how to use the already compiled Yocto ARM64 SDK with Qt5 support;
• how to configure and use it inside Qt Creator.

Including Qt X-compiling support in Yocto Project standard SDK

See: Prepare SDK Image

Sumo distribution for ARM 64-bit target

QtCreator Set Up

The following is an example on how to setup a Yocto Project standard SDK built using Sumo distribution for a Linux x86_64 host in Qt Creator 5.x:

1. open the Tools, Options... menu and select the Kits section
2. use <sdk-install-path>/sysroots/x86_64-pokysdk-linux/usr/bin/qt5/qmake as qmake location in Qt versions tab:
3. use <sdk-install-path>/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux/aarch64-poky-linux-gcc as C compiler path and select ABI arm-linux-generic-elf-64bit in the Compilers tab:
4. use <sdk-install-path>/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux/aarch64-poky-linux-g++ as C++ compiler path and select ABI arm-linux-generic-elf-64bit in the Compilers tab:
5. use <sdk-install-path>/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux/aarch64-poky-linux-gdb as debugger path in Debuggers tab:
6. open the Devices section
7. in the Devices tab create a new device of type Generic Linux Device, specify IP address and authentication details:
8. return to the Kits section
9. create a new kit with name X-compile ARM 64bit selecting the configurations we just created use <sdk-install-path>/sysroots/aarch64-poky-linux as sysroot path
10. press Apply and exit Qt Creator

GUI Buid Method

11. open a terminal application and source the cross compiling environment setup with:
    . <sdk-install-path>/environment-setup-aarch64-poky-linux

12. start Qt Creator from the current command line:
    qtcreator

13. create a new example project using the Qt Widgets Application template

14. name the project hello-qt

15. select the X-compile ARM 64bit kit we just created and finish

16. edit the hello-qt.pro adding:
    
    # install
    target.path=/home/root/
    INSTALLS += target

17. Build the project

18. Run

19. the hello-qt application should now start on the target embedded Linux device. Success!

Command Line Build Method

20. open a terminal application and source the cross compiling environment setup with:
    . <sdk-install-path>/environment-setup-aarch64-poky-linux

21. make the Qt5 SDK examples available for the developer:
    sudo chown ${USER}:${USER} -R <sdk-install-path>/sysroots/aarch64-poky-linux/usr/share/qt5/examples

22. goto an opengl/hellogl2 directory:
    cd <sdk-install-path>/sysroots/aarch64-poky-linux/usr/share/qt5/examples/opengl/hellogl2

23. issue this sequence:
    qmake -config release
make -j 8

24. issue file command and make sure that the produced binary is an ARM64 executable file:
    file hellogl2 | grep -q aarch64 && echo "good" || echo "bad"

25. if it is a good, then copy this binary file to the target device and run it.