## table of contents

SCALBLN(3) | Linux Programmer's Manual | SCALBLN(3) |

# 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
***exp***);**

**float scalblnf(float ***x***, long ***exp***);**

**long double scalblnl(long double ***x***, long
***exp***);**

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

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

**long double scalbnl(long double ***x***, int
***exp***);**

Link with *-lm*.

**scalbln**(), **scalblnf**(), **scalblnl**():

|| /* Since glibc 2.19: */ _DEFAULT_SOURCE

**scalbn**(),

**scalbnf**(),

**scalbnl**():

|| /* Since glibc 2.19: */ _DEFAULT_SOURCE

|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

# 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
*errno*is set to**ERANGE**. An underflow floating-point exception (**FE_UNDERFLOW**) is raised.

# VERSIONS¶

These functions first appeared in glibc in version 2.1.

# ATTRIBUTES¶

For an explanation of the terms used in this section, see attributes(7).

Interface |
Attribute |
Value |

scalbn (), scalbnf (), scalbnl (), scalbln (), scalblnf (), scalblnl () | Thread safety | MT-Safe |

# CONFORMING TO¶

C99, POSIX.1-2001, POSIX.1-2008.

# 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).

# BUGS¶

Before glibc 2.20, these functions did not set *errno* for
range errors.

# SEE ALSO¶

# COLOPHON¶

This page is part of release 5.10 of the Linux *man-pages*
project. A description of the project, information about reporting bugs, and
the latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.

2020-11-01 |