Cross-compilation

Cross-compilation is not a special mode in Zig. It is a flag:

zig build-exe main.zig -target x86_64-linux-gnu
zig build-exe main.zig -target aarch64-macos
zig build-exe main.zig -target x86_64-windows-gnu
zig build-exe main.zig -target wasm32-wasi

No cross toolchain to install, no sysroot to assemble. Zig ships libc sources for the targets it supports and builds what it needs on demand.

zig targets       # everything available

The triple

<arch>-<os>-<abi>, with native allowed in any position:

x86_64-linux-gnu
x86_64-linux-musl      # static linking without glibc's baggage
aarch64-macos-none
wasm32-wasi
native-native-musl

The ABI field matters more than people expect. musl produces a genuinely static binary; gnu links against glibc and inherits its version compatibility rules.

Targeting a specific CPU

zig build-exe main.zig -target x86_64-linux -mcpu=znver3
zig build-exe main.zig -mcpu=baseline        # maximum portability

baseline is the conservative choice: no assumptions beyond the architecture minimum. Naming a specific CPU lets the optimiser use its instructions, at the cost of not running on older ones.

In build.zig

const target = b.standardTargetOption(.{});

That exposes -Dtarget= to whoever runs your build, so users can cross-compile your project without you doing anything else.

Compiling C too

zig cc is a drop-in C compiler with the same cross-compilation story, which is why some projects adopt Zig purely as a build tool for their existing C.