# scalb

```SCALB(3)                   Linux Programmer's Manual                  SCALB(3)

NAME
scalb,  scalbf,  scalbl  -  multiply  floating-point number by integral
power of radix (OBSOLETE)

SYNOPSIS
#include <math.h>

double scalb(double x, double exp);
float scalbf(float x, float exp);
long double scalbl(long double x, long double exp);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

scalb():
_XOPEN_SOURCE >= 500
|| /* Since glibc 2.19: */ _DEFAULT_SOURCE
|| /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
scalbf(), scalbl():
_XOPEN_SOURCE >= 600
|| /* 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 or exp is a NaN, a NaN is returned.

If  x is positive infinity (negative infinity), and exp is not negative
infinity, positive infinity (negative infinity) is returned.

If x is +0 (-0), and exp is not positive infinity, +0 (-0) is returned.

If x is zero, and exp is positive infinity, a domain error occurs,  and
a NaN is returned.

If  x  is an infinity, and exp is negative infinity, a domain error oc-
curs, and a NaN 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  re-
turn 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:

Domain error: x is 0, and exp is positive infinity, or  x  is  positive
infinity  and  exp is negative infinity and the other argument is not a
NaN
An invalid floating-point exception (FE_INVALID) is raised.

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.

ATTRIBUTES
For an  explanation  of  the  terms  used  in  this  section,  see  at-
tributes(7).

+-----------------------------+---------------+---------+
|Interface                    | Attribute     | Value   |
+-----------------------------+---------------+---------+
|scalb(), scalbf(), scalbl()  | Thread safety | MT-Safe |
+-----------------------------+---------------+---------+
CONFORMING TO
scalb()   is   specified   in  POSIX.1-2001,  but  marked  obsolescent.
POSIX.1-2008 removes the specification of scalb(), recommending the use
of  scalbln(3), scalblnf(3), or scalblnl(3) instead.  The scalb() func-
tion is from 4.3BSD.

scalbf() and scalbl()  are  unstandardized;  scalbf()  is  nevertheless
present on several other systems