Zig Academy · Lesson

packed struct for Exact Layout

Lay out bits with no padding.

Layout Matters

Sometimes you need bytes laid out in an exact shape, like a hardware register or a network packet. That is when a packed struct shines.

A plain struct lets Zig reorder and pad fields for speed, so its in-memory size may be larger than the sum of its parts.

const Plain = struct {
    flag: bool,
    value: u32,
};