Zig 0.17.0-dev (Split by item)

Shortcut keys
?
Show these tips
S
Focus search field
Esc
Clear focus & close tips
U
Jump to source code
↑
Move up in search results
↓
Move down in search results
↵
Go to active search result
This is an example of documentation generated by ZigDoc, an alternative to Zig's built-in Auto Doc feature. See also examples in other modes/formats. The project being documented here (as the example) is the Zig standard library. Public Namespace

copysign

Public Namespace

Namespaces

Functions

pub fn expect(ok: bool) !void

This function is intended to be used only in tests. When ok is false, returns a test failure error.

pub fn copysign(magnitude: anytype, sign: @TypeOf(magnitude)) @TypeOf(magnitude)

Returns a value with the magnitude of magnitude and the sign of sign.

File

math/copysign.zig
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
const std = @import("../std.zig");
const math = std.math;
const expect = std.testing.expect;

/// Returns a value with the magnitude of `magnitude` and the sign of `sign`.
pub fn copysign(magnitude: anytype, sign: @TypeOf(magnitude)) @TypeOf(magnitude) {
    const T = @TypeOf(magnitude);
    const TBits = @Int(.unsigned, @typeInfo(T).float.bits);
    const sign_bit_mask = @as(TBits, 1) << (@bitSizeOf(T) - 1);
    const mag = @as(TBits, @bitCast(magnitude)) & ~sign_bit_mask;
    const sgn = @as(TBits, @bitCast(sign)) & sign_bit_mask;
    return @as(T, @bitCast(mag | sgn));
}

test copysign {
    inline for ([_]type{ f16, f32, f64, f80, f128 }) |T| {
        try expect(copysign(@as(T, 1.0), @as(T, 1.0)) == 1.0);
        try expect(copysign(@as(T, 2.0), @as(T, -2.0)) == -2.0);
        try expect(copysign(@as(T, -3.0), @as(T, 3.0)) == 3.0);
        try expect(copysign(@as(T, -4.0), @as(T, -4.0)) == -4.0);
        try expect(copysign(@as(T, 5.0), @as(T, -500.0)) == -5.0);
        try expect(copysign(math.inf(T), @as(T, -0.0)) == -math.inf(T));
        try expect(copysign(@as(T, 6.0), -math.nan(T)) == -6.0);
    }
}