zig-build-system

Zig Build System

Purpose

Guide agents through writing build.zig files: executables, libraries, C source integration, build options, test configuration, and build.zig.zon package manifests.

Triggers

• "How do I set up a build.zig file?"
• "How do I add a C library to a Zig project?"
• "How do I define build-time options in Zig?"
• "How do I run Zig tests with zig build test?"
• "What is build.zig.zon and how do I use it?"
• "How do I add a Zig package dependency?"

Workflow

1. Project initialization

# Initialize a new project
mkdir myproject && cd myproject
zig init          # creates src/main.zig and build.zig

# Build
zig build

# Run
zig build run

# Test
zig build test

2. build.zig structure

const std = @import("std");

pub fn build(b: *std.Build) void {
    // Standard options (--optimize, --target)
    const optimize = b.standardOptimizeOption(.{});
    const target = b.standardTargetOptions(.{});

    // Executable
    const exe = b.addExecutable(.{
        .name = "myapp",
        .root_source_file = b.path("src/main.zig"),
        .target = target,
        .optimize = optimize,
    });

    // Install step (zig build → copies to zig-out/bin/)
    b.installArtifact(exe);

    // Run step (zig build run)
    const run_cmd = b.addRunArtifact(exe);
    run_cmd.step.dependOn(b.getInstallStep());
    if (b.args) |args| {
        run_cmd.addArgs(args);
    }
    const run_step = b.step("run", "Run the app");
    run_step.dependOn(&run_cmd.step);

    // Test step (zig build test)
    const unit_tests = b.addTest(.{
        .root_source_file = b.path("src/main.zig"),
        .target = target,
        .optimize = optimize,
    });
    const run_unit_tests = b.addRunArtifact(unit_tests);
    const test_step = b.step("test", "Run unit tests");
    test_step.dependOn(&run_unit_tests.step);
}

3. Libraries

// Static library
const lib = b.addStaticLibrary(.{
    .name = "mylib",
    .root_source_file = b.path("src/mylib.zig"),
    .target = target,
    .optimize = optimize,
});
b.installArtifact(lib);

// Shared library
const shared_lib = b.addSharedLibrary(.{
    .name = "mylib",
    .root_source_file = b.path("src/mylib.zig"),
    .target = target,
    .optimize = optimize,
    .version = .{ .major = 1, .minor = 0, .patch = 0 },
});
b.installArtifact(shared_lib);

// Link library into executable
exe.linkLibrary(lib);