SCALBLN(3) Linux Programmer's Manual SCALBLN(3)
NAME
scalbn, scalbnf, scalbnl, scalbln, scalblnf, scalblnl - multiply float-
ing-point number by integral power of radix
SYNOPSIS
#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
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 is a NaN, a NaN is returned.
If x is positive infinity (negative infinity), positive infinity (nega-
tive 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 re-
turn 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.
VERSIONS
These functions first appeared in glibc in version 2.1.
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(7).
┌──────────────────────────────────┬───────────────┬─────────┐
│Interface │ Attribute │ Value │
├──────────────────────────────────┼───────────────┼─────────┤
│scalbn(), scalbnf(), scalbnl(), │ Thread safety │ MT-Safe │
│scalbln(), scalblnf(), scalblnl() │ │ │
└──────────────────────────────────┴───────────────┴─────────┘
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
NOTES
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).
BUGS
Before glibc 2.20, these functions did not set errno for range errors.
SEE ALSO
ldexp(3), scalb(3)
COLOPHON
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/.
2020-11-01 SCALBLN(3)
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