## Name

scalbn, scalbnf, scalbnl, scalbln, scalblnf, scalblnl — multiply floating-point number by integral power of radix

## Synopsis

```#include <math.h>
```
 ```double scalbln(``` double x, long int exp`)`;

 ```float scalblnf(``` float x, long int exp`)`;

 ```long double scalblnl(``` long double x, long int exp`)`;

 ```double scalbn(``` double x, int exp`)`;

 ```float scalbnf(``` float x, int exp`)`;

 ```long double scalbnl(``` long double x, int exp`)`; Note
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
`scalbln`(), `scalblnf`(), `scalblnl`():
`_XOPEN_SOURCE` >= 600 || `_ISOC99_SOURCE` || `_POSIX_C_SOURCE` >= 200112L;
or cc `-std=c99`
`scalbn`(), `scalbnf`(), `scalbnl`():
`_BSD_SOURCE` || `_SVID_SOURCE` || `_XOPEN_SOURCE` >= 600 || `_ISOC99_SOURCE` || `_POSIX_C_SOURCE` >= 200112L;
or cc `-std=c99`
Note Link with `−lm`.

## DESCRIPTION

These functions multiply their first argument `x` by `FLT_RADIX` (probably 2) to the power of `exp`, that is:

```    x * FLT_RADIX ** exp
```

The definition of `FLT_RADIX` can be obtained by including `<``float.h``>`

## RETURN VALUE

On success, these functions return `x` * `FLT_RADIX` ** `exp`.

If `x` is a NaN, a NaN is returned.

If `x` is positive infinity (negative infinity), positive infinity (negative infinity) is returned.

If `x` is +0 (−0), +0 (−0) is returned.

If the result overflows, a range error occurs, and the functions return `HUGE_VAL`, `HUGE_VALF`, or `HUGE_VALL`, respectively, with a sign the same as `x`.

If the result underflows, a range error occurs, and the functions return zero, with a sign the same as `x`.

## ERRORS

See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

The following errors can occur:

Range error, overflow

An overflow floating-point exception (`FE_OVERFLOW`) is raised.

Range error, underflow

An underflow floating-point exception (`FE_UNDERFLOW`) is raised.

These functions do not set `errno`.

## VERSIONS

These functions first appeared in glibc in version 2.1.

## ATTRIBUTES

### Multithreading (see pthreads(7))

The `scalbn`(), `scalbnf`(), `scalbnl`(), `scalbln`(), `scalblnf`(), and `scalblnl`() functions are thread-safe.

## CONFORMING TO

C99, POSIX.1-2001.

## NOTES

These functions differ from the obsolete functions described in scalb(3) in the type of their second argument. The functions described on this page have a second argument of an integral type, while those in scalb(3) have a second argument of type double.

If `FLT_RADIX` equals 2 (which is usual), then `scalbn`() is equivalent to ldexp(3).

## COLOPHON

This page is part of release 3.52 of the Linux `man-pages` project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man−pages/.

 Copyright 2004 Andries Brouwer . and Copyright 2008, Linux Foundation, written by Michael Kerrisk      %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date.  The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein.  The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END