ATANH
Section: Linux Programmer's Manual (3)
Updated: 2010-09-11
NAME
atanh, atanhf, atanhl - inverse hyperbolic tangent function
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 3.27 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/.
Index
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- CONFORMING TO
-
- BUGS
-
- SEE ALSO
-
- COLOPHON
-
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Time: 07:35:17 GMT, March 26, 2013