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

**#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***);**
Link with

*-lm*.

Feature Test Macro Requirements for glibc (see

**feature_test_macros**(7)):

**scalbln**(),

**scalblnf**(),

**scalblnl**():

_ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L

|| /* Since glibc 2.19: */ _DEFAULT_SOURCE

**scalbn**(),

**scalbnf**(),

**scalbnl**():

_ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L

|| /* Since glibc 2.19: */ _DEFAULT_SOURCE

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

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>*.

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*.

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*.

These functions first appeared in glibc in version 2.1.

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 |

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

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).

**ldexp**(3),

**scalb**(3)