Negative zero literal in golang

Question

IEEE754 supports the negative zero. But this code

a  := -0.0
fmt.Println(a, 1/a)

outputs

0 +Inf

where I would have expected

-0 -Inf

Other languages whose float format is based on IEEE754 let you create negative zero literals

Java :

float a = -0f;
System.out.printf("%f %f", a, 1/a); // outputs "-0,000000 -Infinity"

C# :

var a = -0d;
Console.WriteLine(1/a); // outputs "-Infinity"

Javascript :

​var a = -0;
console.log(a, 1/a);​ // logs "0 -Infinity"

But I couldn't find the equivalent in Go.

How do you write a negative zero literal in go ?

Answer 1

There is a registered issue.

And it happens to give a kind of solution :

a := math.Copysign(0, -1)

It's not so bad as it obviously refers to the standard copysign function defined by IEEE754.

But this means you need to import a package and this still looks much too heavy for the (admittedly minor and rare) need.

Answer 2

package main

import (
        "fmt"
        "math"
)

func main() {
        a := 1. / math.Inf(-1)
        fmt.Println(a, 1/a)
}

(Also here)

---

Output:

-0 -Inf

Answer 3

I just tried out this and it seems to work for me .

package main

import (
    "fmt"
    )

func main() {
    zero := float64(0)
    neg_zero := -zero
    fmt.Println(zero, neg_zero)
}

Though it does not work as expected when I do neg_zer0 := - float64(0)