Manual Reference Pages - ATANH (3)
NAME
atanh, atanhf, atanhl - inverse hyperbolic tangent function
CONTENTS
Synopsis
Description
Errors
Bugs
Colophon
SYNOPSIS
#include <math.h>
double atanh(double x );
float atanhf(float x );
long double atanhl(long double x );

Link with -lm .
Feature Test Macro Requirements for glibc (see
feature_test_macros (7)):

atanh ():

_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 500 ||
_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or
cc -std=c99
atanhf (),
atanhl ():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or
cc -std=c99
DESCRIPTION
The
atanh () function calculates the inverse hyperbolic tangent of
x ; that is the value whose hyperbolic tangent is x .
RETURN VALUE
On success, these functions return the inverse hyperbolic tangent of
x .
If
x is a NaN, a NaN is returned.

If
x is +0 (-0), +0 (-0) is returned.

If
x is +1 or -1,
a pole error occurs,
and the functions return
HUGE_VAL ,
HUGE_VALF , or
HUGE_VALL , respectively, with the mathematically correct sign.

If the absolute value of
x is greater than 1,
a domain error occurs,
and a NaN is returned.

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:

Domain error: x less than -1 or greater than +1
errno is set to
EDOM . An invalid floating-point exception
(FE_INVALID ) is raised.
Pole error: x is +1 or -1
errno is set to
ERANGE (but see BUGS).
A divide-by-zero floating-point exception
(FE_DIVBYZERO ) is raised.

CONFORMING TO
C99, POSIX.1-2001.
The variant returning
double also conforms to
SVr4, 4.3BSD, C89.
BUGS
In glibc 2.9 and earlier,
when a pole error occurs,
errno as set to
EDOM instead of the POSIX-mandated
ERANGE . Since version 2.10, glibc does the right thing.
SEE ALSO
acosh (3),
asinh (3),
catanh (3),
cosh (3),
sinh (3),
tanh (3)
COLOPHON
This page is part of release 3.44 of the Linux
man-pages project.
A description of the project,
and information about reporting bugs,
can be found at
http://www.kernel.org/doc/man-pages /.

Please enable JavaScript to view the comments powered by Disqus.
blog comments powered by