.. redirect-from:: Concepts/About-Cross-Compilation Cross-compilation ================= .. contents:: Table of Contents :local: Overview -------- Open Robotics provides pre-built ROS 2 packages for multiple platforms, but a number of developers still rely on `cross-compilation `__ for different reasons such as: - The development machine does not match the target system. - Tuning the build for specific core architecture (e.g. setting -mcpu=cortex-a53 -mfpu=neon-fp-armv8 when building for Raspberry Pi3). - Targeting a file system other than the ones supported by the pre-built images released by Open Robotics. How does it work ? ------------------ Cross-compiling simple software (e.g. no dependencies on external libraries) is relatively simple and only requiring a cross-compiler toolchain to be used instead of the native toolchain. There are a number of factors which make this process more complex: - The software being built must support the target architecture. Architecture specific code must be properly isolated and enabled during the build according to the target architecture. Examples include assembly code. - All dependencies (e.g. libraries) must be present, either as pre-built or cross-compiled packages, before the target software using them is cross-compiled. - When building software stacks (as opposed to standalone software) using build tools (e.g. colcon), it is expected that the build tool provides a mechanism to allow the developer to enable cross-compilation on the underlying build system used by each piece of software in the stack. Alternatives ------------ An alternative to cross-compilation is to `build multi-platform Docker images `__ using ``docker buildx``.