In this post, we will explore how Docker can be utilized for cross-compiling C++ code specifically for embedded targets. Cross-compiling allows us to compile code on one machine (the host) for a different machine (the target), typically with different architectures or operating systems.

Why use Docker for cross-compiling?

Cross-compiling C++ code for embedded targets can be a complex task due to the differences in toolchains, libraries, and dependencies between the host and target environments. Docker provides a convenient solution by encapsulating the build environment into a container. This ensures reproducibility and eliminates the need to set up and maintain the cross-compilation environment on the host machine.

Setting up the Docker environment

To get started, we need to set up a Docker environment with the necessary tools and libraries for cross-compiling. This involves creating a Dockerfile that defines the build environment and dependencies.

# Base image
FROM debian:buster

# Install cross-compilation tools
RUN apt-get update && \
    apt-get install -y gcc-arm-linux-gnueabihf g++-arm-linux-gnueabihf

# Set environment variables
ENV CROSS_COMPILE arm-linux-gnueabihf-
ENV CC ${CROSS_COMPILE}gcc
ENV CXX ${CROSS_COMPILE}g++

In this example, we are using a Debian-based image as the base for our Docker container. We then install the cross-compilation tools necessary for compiling C++ code for ARM-based embedded targets.

Building the Docker container

Once the Dockerfile is ready, we can build the Docker container using the following command:

docker build -t cross-compiler .

This command will build the Docker container based on the Dockerfile, tag it as “cross-compiler”, and create an image with the necessary tools and environment variables.

Cross-compiling C++ code

To cross-compile our C++ code using the Docker container, we need to mount the source code directory and execute the compilation command inside the container.

docker run -v /path/to/source:/app cross-compiler bash -c "cd /app && $CXX -o myapp myapp.cpp"

In this command, we mount the source code directory /path/to/source to the /app directory inside the container. Then, we execute the compilation command specified by the environment variables ($CXX) using the desired filenames.

Conclusion

Using Docker for cross-compiling C++ code for embedded targets provides a convenient and reproducible solution by encapsulating the necessary build environment into a container. This eliminates the need to set up and maintain the cross-compilation environment on the host machine, making the process more efficient and scalable.

#docker #crosscompiling