Crosscompilation

Cross-compilation is the process of building executable code on a host system for a different target system. The host and the target can differ in processor architecture, operating system, or both. Cross-compilation is essential when the targetHardware is unavailable or impractical to use for development, such as embedded devices, mobile platforms, or specialized appliances.

A cross-compiler toolchain lies at the core of cross-compilation. It includes a compiler, assembler, linker, and related binary utilities configured to generate code for the target. The toolchain may also include a C library and header files for the target (the sysroot). Build systems must be directed to use the cross tools, typically by setting environment variables such as CC, CXX, AR, and AS, and by specifying the host or target triplet. Autotools-based projects can be configured with --host to indicate cross-compilation, while CMake and Meson have their own settings for cross builds.

Common challenges include handling differences in endianness and application binary interface (ABI), ensuring availability of target libraries and runtime support, and maintaining toolchain compatibility. Debugging can be more difficult, and some projects require bootstrapping a minimal target environment before building further software. Static versus dynamic linking and correct library paths in the sysroot are frequent considerations.

Cross-compilation is widely used in operating system development, package creation for non-native architectures, and software development for embedded systems. Examples include toolchains for ARM or MIPS targets, Android NDK workflows, and Linux distributions that build packages for arm, s390x, or x86_64 from x86 hosts. Prebuilt toolchains from organizations like Linaro or distributions aid setup, while toolchain builders such as Crosstool-NG or Buildroot streamline the creation of complete cross environments.