zig/test/cases/bitcast.zig

const std = @import("std");
const assert = std.debug.assert;
const maxInt = std.math.maxInt;

test "@bitCast i32 -> u32" {
    testBitCast_i32_u32();
    comptime testBitCast_i32_u32();
}

fn testBitCast_i32_u32() void {
    assert(conv(-1) == maxInt(u32));
    assert(conv2(maxInt(u32)) == -1);
}

fn conv(x: i32) u32 {
    return @bitCast(u32, x);
}
fn conv2(x: u32) i32 {
    return @bitCast(i32, x);
}

test "@bitCast extern enum to its integer type" {
    const SOCK = extern enum {
        A,
        B,

        fn testBitCastExternEnum() void {
            var SOCK_DGRAM = @This().B;
            var sock_dgram = @bitCast(c_int, SOCK_DGRAM);
            assert(sock_dgram == 1);
        }
    };

    SOCK.testBitCastExternEnum();
    comptime SOCK.testBitCastExternEnum();
}