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)