Qt X Compiling

Intro

Development of Qt based applications for Embedded Linux systems often needs to be done on a host machine with a different architecture. The following document outlines the configuration steps required in order to prepare the host machine for cross-compiling.

Document contents:

• Setting up Yocto SDK with Qt5 support
• Qt Development Environment Prerequisites
• Using Yocto SDK without QtCreator
• Using Yocto SDK with QtCreator:
  • Configuring QtCreator for use with Yocto SDK
  • Building a project using QtCreator

Qt Development Environment Prerequisites

Assumptions

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

Requirements

• Linux Debian/Ubuntu desktop
• Install build-essential:

  sudo apt-get install build-essential

• Install QtCreator:

  sudo apt-get install qtcreator

• Yocto 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 enabled:

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

Using Yocto SDK without QtCreator

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

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

• make the Qt5 SDK examples available for the developer:

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

• go to opengl/hellogl2 project directory:

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

• issue the following sequence:

qmake -config release
make -j 8

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

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

• if the file is good, copy this binary file to the target device and run it.
• if the file is bad, re-issue the entire procedure.

Configuring QtCreator for use with Yocto SDK

The following example shows how to setup QtCreator with Yocto Project SDK built using Sumo distribution for a Linux x86_64 host:

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

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

• in the same terminal window start QtCreator:

  qtcreator

• open the Tools, Options... menu and select the Kits section

• use the following line as qmake location in Qt versions tab:

  /opt/fsl-imx-xwayland/4.14-sumo/sysroots/x86_64-pokysdk-linux/usr/bin/qt5/qmake

  

• use the following line as C compiler path and select ABI arm-linux-generic-elf-64bit in the Compilers tab:

  /opt/fsl-imx-xwayland/4.14-sumo/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux/aarch64-poky-linux-gcc

  

• use the following line as C++ compiler path and select ABI arm-linux-generic-elf-64bit in the Compilers tab:

  /opt/fsl-imx-xwayland/4.14-sumo/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux/aarch64-poky-linux-g++

  

• use the following line as debugger path in Debuggers tab:

  /opt/fsl-imx-xwayland/4.14-sumo/sysroots/x86_64-pokysdk-linux/usr/bin/aarch64-poky-linux/aarch64-poky-linux-gdb

  

• 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 the following line as sysroot path:

  /opt/fsl-imx-xwayland/4.14-sumo/sysroots/aarch64-poky-linux

  
• click Apply and exit Qt Creator

Building a project using QtCreator

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

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

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

• start QtCreator in the same terminal window:

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