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, double exp);
long double scalbl(long double x, double exp);
Link with -lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
scalb(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500
scalbf(), scalbl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600
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.
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 3.24 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/.
2009-03-15