ACOSH
Section: Linux Programmer's Manual (3)
Updated: 20100920
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NAME
acosh, acoshf, acoshl  inverse hyperbolic cosine function
SYNOPSIS
#include <math.h>
double acosh(double x);
float acoshf(float x);
long double acoshl(long double x);
Link with
lm.
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
acosh():

_BSD_SOURCE  _SVID_SOURCE  _XOPEN_SOURCE >= 500 
_XOPEN_SOURCE && _XOPEN_SOURCE_EXTENDED  _ISOC99_SOURCE 
_POSIX_C_SOURCE >= 200112L;
or
cc std=c99
acoshf(),
acoshl():

_BSD_SOURCE  _SVID_SOURCE  _XOPEN_SOURCE >= 600  _ISOC99_SOURCE 
_POSIX_C_SOURCE >= 200112L;
or
cc std=c99
DESCRIPTION
The
acosh()
function calculates the inverse hyperbolic cosine of
x;
that is the value whose hyperbolic cosine is
x.
RETURN VALUE
On success, these functions return the inverse hyperbolic cosine of
x.
If
x
is a NaN, a NaN is returned.
If
x
is +1, +0 is returned.
If
x
is positive infinity, positive infinity is returned.
If
x
is less than 1,
a domain error occurs,
and the functions return a NaN.
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 is less than 1

errno
is set to
EDOM.
An invalid floatingpoint exception
(FE_INVALID)
is raised.
CONFORMING TO
C99, POSIX.12001.
The variant returning
double
also conforms to
SVr4, 4.3BSD, C89.
SEE ALSO
asinh(3),
atanh(3),
cacosh(3),
cosh(3),
sinh(3),
tanh(3)
COLOPHON
This page is part of release 3.74 of the Linux
manpages
project.
A description of the project,
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and the latest version of this page,
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http://www.kernel.org/doc/manpages/.
Index
 NAME

 SYNOPSIS

 DESCRIPTION

 RETURN VALUE

 ERRORS

 CONFORMING TO

 SEE ALSO

 COLOPHON
