Cross compilation

By default, Zig will compile for your combination of CPU and OS. This can be overridden by -target. Let's compile our tiny hello world to a 64 bit arm linux platform.

zig build-exe .\tiny-hello.zig -O ReleaseSmall -fstrip -fsingle-threaded -target aarch64-linux

QEMU or similar may be used to conveniently test executables made for foreign platforms.

Some CPU architectures that you can cross-compile for:

• x86_64
• arm
• aarch64
• i386
• riscv64
• wasm32

Some operating systems you can cross-compile for:

• linux
• macos
• windows
• freebsd
• netbsd
• dragonfly
• UEFI

Many other targets are available for compilation, but aren't as well tested as of now. See Zig's support table for more information; the list of well tested targets is slowly expanding.

As Zig compiles for your specific CPU by default, these binaries may not run on other computers with slightly different CPU architectures. It may be useful to instead specify a specific baseline CPU model for greater compatibility. Note: choosing an older CPU architecture will bring greater compatibility, but means you also miss out on newer CPU instructions; there is an efficiency/speed versus compatibility trade-off here.

Let's compile a binary for a sandybridge CPU (Intel x86_64, circa 2011), so we can be reasonably sure that someone with an x86_64 CPU can run our binary. Here we can use native in place of our CPU or OS, to use our system's.

zig build-exe .\tiny-hello.zig -target x86_64-native -mcpu sandybridge

Details on what architectures, OSes, CPUs and ABIs (details on ABIs in the next chapter) are available can be found by running zig targets. Note: the output is long, and you may want to pipe it to a file, e.g. zig targets > targets.json.