1/7 test "enum ordinal value"... OK
2/7 test "set enum ordinal value"... OK
3/7 test "enum method"... OK
4/7 test "enum variant switch"... OK
5/7 test "@TagType"... OK
6/7 test "@typeInfo"... OK
7/7 test "@tagName"... OK
All 7 tests passed.

See also:

• @typeInfo
• @sizeOf

By default, enums are not guaranteed to be compatible with the C ABI:

test.zig

const Foo = enum { a, b, c };
export fn entry(foo: Foo) void { }

$ zig build-obj test.zig
./docgen_tmp/test.zig:2:22: error: parameter of type 'Foo' not allowed in function with calling convention 'C'
export fn entry(foo: Foo) void { 
                     ^

For a C-ABI-compatible enum, use extern enum:

By default, the size of enums is not guaranteed.

packed enum causes the size of the enum to be the same as the size of the integer tag type of the enum:

test.zig

const std = @import("std");
test "packed enum" {
        one,
        two,
        three,
    };
    std.testing.expect(@sizeOf(Number) == @sizeOf(u8));
}

$ zig test test.zig
1/1 test "packed enum"... OK
All 1 tests passed.

This makes the enum eligible to be in a .

test.zig

$ zig test test.zig
1/2 test "enum literals"... OK
2/2 test "switch using enum literals"... OK
All 2 tests passed.

A Non-exhaustive enum can be created by adding a trailing ‘_‘ field. It must specify a tag type and cannot consume every enumeration value.

@intToEnum on a non-exhaustive enum cannot fail.

A switch on a non-exhaustive enum can include a ‘_‘ prong as an alternative to an else prong with the difference being that it makes it a compile error if all the known tag names are not handled by the switch.

const std = @import("std");
const expect = std.testing.expect;
const Number = enum(u8) {
    one,
    _,
};
test "switch on non-exhaustive enum" {
    const number = Number.one;
    const result = switch (number) {
        .one => true,
        .two,
        .three => false,
        _ => false,
    };
    expect(result);
    const is_one = switch (number) {
        .one => true,
        else => false,
    };
    expect(is_one);
}

$ zig test test.zig
1/1 test "switch on non-exhaustive enum"... OK