crosscompiling

Cross compiling is the process of compiling software on a host system to run on a different target system, using a cross compiler that produces executables for the target architecture. The host and target may differ in CPU architecture, operating system, or application binary interface (ABI). A typical cross toolchain includes a cross compiler (for example, arm-linux-gnueabihf-gcc or aarch64-linux-gnu-gcc), a linker, assembler tools, and a set of libraries built for the target (the sysroot).

Toolchains are used by configuring builds to use the cross compiler as the primary compiler. Build systems expose this through environment variables (such as CC, CXX, AR, and LD) or triplet-based options (for example, --host/--build/--target in Autotools). The sysroot provides the target’s headers and libraries so that code links against the correct runtime and APIs.

Typical workflows involve installing a prebuilt cross toolchain for the desired target (for instance, gcc-aarch64-linux-gnu on Debian/Ubuntu or mingw-w64 for Windows targets), or constructing a custom toolchain with tools like crosstool-ng. A properly prepared sysroot and correct toolchain prefix are essential for successful cross compilation. Testing often uses emulators such as QEMU or actual target hardware.

Challenges include ABI and endianness differences, availability of target libraries and headers, and matching the target’s dynamic linker and runtime environment. Debugging cross-compiled code may require remote or cross-debugging setups.

Common tools and concepts include GCC and Clang cross compilers, GNU Binutils for cross linking and assembly, crosstool-ng for toolchain creation, target C libraries such as glibc or musl, and testing with emulators or hardware. Cross compiling is widely used for embedded systems, mobile platforms, and cross-platform development workflows.