crosstoolchain

A crosstoolchain is a set of programming tools used to compile software for a target system whose architecture differs from the host machine. It typically includes a cross-compiler (most notably GCC), the associated assembler and linker from the GNU binutils, a C library and headers for the target (such as glibc, musl, or uClibc), and a sysroot containing the target's runtime environment. Together, these components enable building executables on a host computer that will run on embedded devices or other architectures such as ARM, MIPS, PowerPC, or x86_64 hosts building for 32-bit ARM.

A cross toolchain is usually organized with a prefix naming convention (for example arm-linux-gnueabihf-) to distinguish host and target tools. The toolchain may include the cross-compiled GCC, a linker, assembler, archiver, and debugging tools, plus the target libc and compiler runtime libraries. Many projects provide build systems to configure and assemble the toolchain, including Crosstool-NG, Buildroot, and OpenEmbedded. Toolchains may be prebuilt for common targets or built from source.

Usage involves selecting the correct prefix, updating the PATH to include the toolchain bin directory, and configuring builds to use the cross-compiler by setting variables such as CC, CXX, AR, and RANLIB, or by passing --host/--target to configure scripts. The sysroot is used to provide the target headers and libraries during compilation and linking. Cross toolchains are essential in embedded development, cross-compiling Linux distributions, and anywhere the host architecture differs from the target.

Considerations include compatibility with the desired C library and ABI, performance, licensing, and updates. Some environments favor musl or uClibc instead of glibc for smaller footprints. Bare-metal toolchains may omit libc entirely. Proper versioning and reproducible builds are important in professional workflows.