Qt X Compiling

Intro

It is a quite common case when developing Qt based applications for an Embedded Linux system is carried out on a host machine with a different architecture. In order to prepare the host machine for X-compiling some manual configuration steps required.

This is a brief manual that shows:

• how to include Qt5 support in Yocto ARM64 standard SDK
  See: Prepare SDK Image
• how to use the SDK with QtCreator
  • how to configure and use the SDK inside QtCreator
  • hot to build a sample project using QtCreator
• how to use the SDK w/out QtCreator
  • command line method

Requirements:

• Linux Debian/Ubuntu desktop
  • Tested desktop:

  uname -r; cat /etc/debian_version
  # Outupt
  4.19.0-5-amd64
  10.0
  

• build-essential
  • Install it this way:

  sudo apt-get install build-essential
  

• QtCreator
  • Install it this way:

  sudo apt-get install qtcreator
  

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 4.8.2:

0. open a terminal application and source the cross compiling environment setup with:

. <sdk-install-path>/environment-setup-aarch64-poky-linux
qtcreator &

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 the opengl/hellogl2 project 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.