How to compile a source into an ARM binary - cmake

Question

I want to compile VTK-DICOM to run on an ARM Raspberry Pi (Raspbian). Is it posible? Where should I start?

Answer 1

Building for Raspbian Debian Buster images and ARMv6
This tutorial also supports older Rasperry Pi (A, B, B+, Zero) based on the ARMv6 CPU.
See also:
GCC 8 Cross Compiler outputs ARMv7 executable instead of ARMv6
Set up the toolchain
There is no official git repository containing an updated toolchain (See https://github.com/raspberrypi/tools/issues/102).
Here is a github repository which includes building and precompiled toolchains for ARMv6 based on GCC8 and newer:
https://github.com/Pro/raspi-toolchain
As mentioned in the project's readme, these are the steps to get the toolchain. You can also build it yourself (see the README for further details).
Download the toolchain:
wget https://github.com/Pro/raspi-toolchain/releases/latest/download/raspi-toolchain.tar.gz
Extract it. Note: The toolchain has to be in /opt/cross-pi-gcc since it's not location independent.
sudo tar xfz raspi-toolchain.tar.gz --strip-components=1 -C /opt
You are done! The toolchain is now in /opt/cross-pi-gcc
Optional, add the toolchain to your path, by adding:
export PATH=$PATH:/opt/cross-pi-gcc/bin
to the end of the file named ~/.bashrc
Now you can either log out and log back in (i.e. restart your terminal session), or run . ~/.bashrc in your terminal to pick up the PATH addition in your current terminal session.
Get the libraries from the Raspberry PI
To cross-compile for your own Raspberry Pi, which may have some custom libraries installed, you need to get these libraries onto your host.
Create a folder $HOME/raspberrypi.
In your raspberrypi folder, make a folder called rootfs.
Now you need to copy the entire /liband /usr directory to this newly created folder. I usually bring the rpi image up and copy it via rsync:
rsync -vR --progress -rl --delete-after --safe-links pi#192.168.1.PI:/{lib,usr,opt/vc/lib} $HOME/raspberrypi/rootfs
where 192.168.1.PI is replaced by the IP of your Raspberry Pi.
Use CMake to compile your project
To tell CMake to take your own toolchain, you need to have a toolchain file which initializes the compiler settings.
Get this toolchain file from here:
https://github.com/Pro/raspi-toolchain/blob/master/Toolchain-rpi.cmake
Now you should be able to compile your cmake programs simply by adding this extra flag: -D CMAKE_TOOLCHAIN_FILE=$HOME/raspberrypi/pi.cmake and setting the correct environment variables:
export RASPBIAN_ROOTFS=$HOME/raspberry/rootfs
export PATH=/opt/cross-pi-gcc/bin:$PATH
export RASPBERRY_VERSION=1
cmake -DCMAKE_TOOLCHAIN_FILE=$HOME/raspberry/Toolchain-rpi.cmake ..
An example hello world is shown here:
https://github.com/Pro/raspi-toolchain/blob/master/build_hello_world.sh
Source:
https://stackoverflow.com/a/58559140/13859552