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Man page of SCALB
SCALB
Section: Linux Programmer's Manual (3)
Updated: 2016-03-15
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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);
Link with -lm.
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 occurs, 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 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:
- 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
attributes(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()
function is from 4.3BSD.
scalbf()
and
scalbl()
are unstandardized;
scalbf()
is nevertheless present on several other systems
SEE ALSO
ldexp(3),
scalbln(3)
COLOPHON
This page is part of release 4.09 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/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- ATTRIBUTES
-
- CONFORMING TO
-
- SEE ALSO
-
- COLOPHON
-
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