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 get Yocto ARM64 SDK with Qt5 support (external links):
  • prepare SDK image with Qt5 support
  • install a pre-built SDK with Qt5 support
• how to use the SDK with QtCreator:
  • configure and use the SDK inside QtCreator
  • build a sample project using QtCreator
• how to use the SDK w/out QtCreator:
  • command line method

Assumptions

• SDK install path is /opt/fsl-imx-xwayland/4.14-sumo

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
  

• Yocto ARM64 SDK with Qt5 support
  • Make sure that the SDK is installed:

  [[ -f /opt/fsl-imx-xwayland/4.14-sumo/environment-setup-aarch64-poky-linux ]] && echo "Installed" || echo "Not Installed"
  

  • Make sure that the Qt5 support is on:

  [[ -f /opt/fsl-imx-xwayland/4.14-sumo/sysroots/x86_64-pokysdk-linux/usr/bin/qt5/qmake ]] && echo "On" || echo "Off"
  

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:

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

. /opt/fsl-imx-xwayland/4.14-sumo/environment-setup-aarch64-poky-linux
qtcreator &

• open the Tools, Options... menu and select the Kits section
• use /opt/fsl-imx-xwayland/4.14-sumo/sysroots/x86_64-pokysdk-linux/usr/bin/qt5/qmake as qmake location in Qt versions tab:
• use /opt/fsl-imx-xwayland/4.14-sumo/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:
• use /opt/fsl-imx-xwayland/4.14-sumo/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:
• use /opt/fsl-imx-xwayland/4.14-sumo/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux/aarch64-poky-linux-gdb as debugger path in Debuggers tab:
• open the Devices section
• in the Devices tab create a new device of type Generic Linux Device, specify IP address and authentication details:
• return to the Kits section
• create a new kit with name X-compile ARM 64bit selecting the configurations we just created use /opt/fsl-imx-xwayland/4.14-sumo/sysroots/aarch64-poky-linux as sysroot path:
• press Apply and exit Qt Creator

GUI Build Method

ℹ️ Make sure that the how to configure and use the SDK inside QtCreator ⤴️ was carried out first.

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

. /opt/fsl-imx-xwayland/4.14-sumo/environment-setup-aarch64-poky-linux

• start Qt Creator from the current command line:

qtcreator

• create a new example project using the Qt Widgets Application template
• name the project hello-qt
• select the X-compile ARM 64bit kit we just created and finish
• edit the hello-qt.pro adding:

# install
target.path=/home/root/
INSTALLS += target

• Build the project
• Run
• the hello-qt application should now start on the target embedded Linux device. Success!

Command Line Build Method

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

. /opt/fsl-imx-xwayland/4.14-sumo/environment-setup-aarch64-poky-linux

• make the Qt5 SDK examples available for the developer:

sudo chown ${USER}:${USER} -R /opt/fsl-imx-xwayland/4.14-sumo/sysroots/aarch64-poky-linux/usr/share/qt5/examples

• goto the opengl/hellogl2 project directory:

cd /opt/fsl-imx-xwayland/4.14-sumo/sysroots/aarch64-poky-linux/usr/share/qt5/examples/opengl/hellogl2

• issue this sequence:

qmake -config release
make -j 8

• issue file command and make sure that the produced binary is an ARM64 executable file:

file hellogl2 | grep -q aarch64 && echo "good" || echo "bad"

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