Build Mode

Build Mode

Zig has four build modes:

Debug (default)
ReleaseFast
ReleaseSafe
ReleaseSmall

To add standard build options to a build.zig file:

const Builder = @import("std").build.Builder;
pub fn build(b: *Builder) void {
    const exe = b.addExecutable("example", "example.zig");
    exe.setBuildMode(b.standardReleaseOptions());
    b.default_step.dependOn(&exe.step);
}

This causes these options to be available:

  -Drelease-safe=[bool] optimizations on and safety on
  -Drelease-fast=[bool] optimizations on and safety off
  -Drelease-small=[bool] size optimizations on and safety off

Debug

$ zig build-exe example.zig

Fast compilation speed
Safety checks enabled
Slow runtime performance
Large binary size
No reproducible build requirement

ReleaseFast

$ zig build-exe example.zig -O ReleaseFast

Fast runtime performance
Safety checks disabled
Slow compilation speed
Large binary size
Reproducible build

ReleaseSafe

$ zig build-exe example.zig -O ReleaseSafe

Medium runtime performance
Safety checks enabled
Slow compilation speed
Large binary size
Reproducible build

ReleaseSmall

$ zig build-exe example.zig -O ReleaseSmall

Medium runtime performance
Safety checks disabled
Slow compilation speed
Small binary size
Reproducible build