Name
ldexp, ldexpf, ldexpl — multiply floating-point 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); |
![[Note]](../stylesheet/note.png) |
Note | ||||
|---|---|---|---|---|---|
|
|
|
Note |
|---|---|
|
Link with |
DESCRIPTION
These functions return the result of multiplying the
floating-point 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
-
errnois set to ERANGE. An overflow floating-point exception (FE_OVERFLOW) is raised. - Range error, underflow
-
errnois 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 |
ldexp(), ldexpf(), ldexpl() |
Thread safety | MT-Safe |
CONFORMING TO
C99, POSIX.1-2001, POSIX.1-2008.
The variant returning double also conforms to SVr4, 4.3BSD, C89.
COLOPHON
This page is part of release 4.07 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/.
|
Copyright 1993 David Metcalfe (davidprism.demon.co.uk) and Copyright 2008, Linux Foundation, written by Michael Kerrisk <mtk.manpagesgmail.com> %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END References consulted: Linux libc source code Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) 386BSD man pages Modified 1993-07-24 by Rik Faith (faithcs.unc.edu) Modified 2004-10-31 by aeb |