scalbln3
Scale by an integer power of radix
Usage
#include <math.h>
double scalbln(double x, long e); float scalblnf(float x, long e); long double scalblnl(long double x, long e);
double scalbn(double x, int e); float scalbnf(float x, int e); long double scalbnl(long double x, int e);
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 <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
Library
Math library (libm, -lm)
Overview
These functions multiply their first argument x by FLT_RADIX (probably 2) to the power of e, that is:
x * FLT_RADIX ** e
The definition of FLT_RADIX can be obtained by including <float.h>.
Return value
On success, these functions return x * FLT_RADIX ** e.
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.
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:
- Range error, overflow
-
An overflow floating-point exception (
FE_OVERFLOW) is raised.
- Range error, underflow
-
errno is set to ERANGE. An underflow floating-point exception (
FE_UNDERFLOW) is raised.
Attributes
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 |
Notes
If FLT_RADIX equals 2 (which is usual), then scalbn() is equivalent to ldexp(3).
Releases
12 releases since Debian 3.1 (Sarge); the text changed 11 times.