---
name: "significand"
section: "3"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux", "freebsd"]
url: "https://new.carta.tech/significand"
---

# significand(3)

get mantissa of floating-point number

## NAME

significand, significandf, significandl - get mantissa of floating-point number

## LIBRARY

Math library (*libm*, *-lm*)

## SYNOPSIS

```
#include <math.h>
```

**double significand(double** *x***);** **float significandf(float** *x***);** **long double significandl(long double** *x***);**

Feature Test Macro Requirements for glibc (see [**feature\_test\_macros**(7)](/feature_test_macros/7.md)):

**significand**(), **significandf**(), **significandl**():

```
    /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
```

## DESCRIPTION

These functions return the mantissa of *x* scaled to the range \[**1**, **FLT\_RADIX**). They are equivalent to

```
scalb(x, (double) -ilogb(x))
```

This function exists mainly for use in certain standardized tests for IEEE 754 conformance.

## ATTRIBUTES

For an explanation of the terms used in this section, see [**attributes**(7)](/attributes/7.md).

| | | |
| --- | --- | --- |
| **Interface** | **Attribute** | **Value** |
| **significand**(), **significandf**(), **significandl**() | Thread safety | MT-Safe |

## STANDARDS

None.

- **significand**()

  BSD.

## HISTORY

- **significand**()

  BSD.

## SEE ALSO

[**ilogb**(3)](/ilogb/3.md), [**scalb**(3)](/scalb/3.md)