scalbn, scalbnf, scalbnl, scalbln, scalblnf, scalblnl - multiply floating-point number by integral power of radix
#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
.
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:
An overflow floating-point exception (FE_OVERFLOW) is raised.
errno
is set to ERANGE. An underflow
floating-point exception (FE_UNDERFLOW) is raised.
These functions first appeared in glibc in version 2.1.
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).
Before glibc 2.20, these functions did not set errno
for
range errors.
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/.