LDEXP
Section: Linux Programmer's Manual (3)
Updated: 20130819
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NAME
ldexp, ldexpf, ldexpl  multiply floatingpoint number by integral power of 2
SYNOPSIS
#include <math.h>
double ldexp(double x, int exp);
float ldexpf(float x, int exp);
long double ldexpl(long double x, int exp);
Link with lm.
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
ldexpf(),
ldexpl():

_BSD_SOURCE  _SVID_SOURCE  _XOPEN_SOURCE >= 600  _ISOC99_SOURCE 
_POSIX_C_SOURCE >= 200112L;
or
cc std=c99
DESCRIPTION
The
ldexp()
function returns the result of multiplying the floatingpoint number
x
by 2 raised to the power
exp.
RETURN VALUE
On success, these functions return
x * (2^exp).
If
exp
is zero, then
x
is returned.
If
x
is a NaN,
a NaN is returned.
If
x
is positive infinity (negative infinity),
positive infinity (negative infinity) is returned.
If the result underflows,
a range error occurs,
and zero 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.
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

errno
is set to
ERANGE.
An overflow floatingpoint exception
(FE_OVERFLOW)
is raised.
 Range error, underflow

errno
is set to
ERANGE.
An underflow floatingpoint exception
(FE_UNDERFLOW)
is raised.
ATTRIBUTES
Multithreading (see pthreads(7))
The
ldexp(),
ldexpf(),
and
ldexpl()
functions are threadsafe.
CONFORMING TO
C99, POSIX.12001.
The variant returning
double
also conforms to
SVr4, 4.3BSD, C89.
SEE ALSO
frexp(3),
modf(3),
scalbln(3)
COLOPHON
This page is part of release 3.54 of the Linux
manpages
project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/manpages/.
Index
 NAME

 SYNOPSIS

 DESCRIPTION

 RETURN VALUE

 ERRORS

 ATTRIBUTES

 Multithreading (see pthreads(7))

 CONFORMING TO

 SEE ALSO

 COLOPHON

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Time: 23:02:11 GMT, January 19, 2018