---
name: "ieee_test"
section: "3"
platform: "freebsd"
package: "base"
version: "16.0-CURRENT-20261027-61c70dc16a79"
release: "FreeBSD 16.0-CURRENT (2026-10-27)"
platforms: ["freebsd"]
url: "https://new.carta.tech/ieee_test"
---

# ieee\_test(3)

IEEE test functions

## NAME

**scalb**, **scalbf**, **significand**, **significandf** – IEEE test functions

## LIBRARY

Math Library (libm, -lm)

## SYNOPSIS

**#include \<math.h\>**

*double*\

**scalb**(*double x*, *double n*);

*float*\

**scalbf**(*float x*, *float n*);

*double*\

**significand**(*double x*);

*float*\

**significandf**(*float x*);

## DESCRIPTION

These functions allow users to test conformance to IEEE Std 754-1985. Their use is not otherwise recommended.

**scalb**(*x*, *n*) and **scalbf**(*x*, *n*) return *x*∗(2\*\**n*) computed by exponent manipulation. If *n* is not an integer, , or an , the result is unspecified.

**significand**(*x*) and **significandf**(*x*) return *sig*, where *x* := *sig* ∗ 2\*\**n* with 1 ≤ *sig* \< 2. **significand**(*x*) and **significandf**(*x*) are not defined when *x* is 0, , or .

## SEE ALSO

[ieee(3)](/ieee/3.md), [math(3)](/math/3.md)

## STANDARDS

IEEE Std 754-1985