NAME
cosh, coshf, coshl - hyperbolic cosine function
SYNOPSIS
#include <math.h>
double cosh(double x);
float coshf(float x);
long double coshl(long double x);
Link with -lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
coshf(), coshl(): _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600
|| _ISOC99_SOURCE; or cc -std=c99
DESCRIPTION
The cosh() function returns the hyperbolic cosine of x, which is
defined mathematically as:
cosh(x) = (exp(x) + exp(-x)) / 2
RETURN VALUE
On success, these functions return the hyperbolic cosine of x.
If x is a NaN, a NaN is returned.
If x is +0 or -0, 1 is returned.
If x is positive infinity or negative infinity, positive infinity is
returned.
If the result overflows, a range error occurs, and the functions return
+HUGE_VAL, +HUGE_VALF, or +HUGE_VALL, respectively.
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: result overflow
errno is set to ERANGE. An overflow floating-point exception
(FE_OVERFLOW) is raised.
CONFORMING TO
C99, POSIX.1-2001. The variant returning double also conforms to SVr4,
4.3BSD.
BUGS
In glibc version 2.3.4 and earlier, an overflow floating-point
(FE_OVERFLOW) exception is not raised when an overflow occurs.
SEE ALSO
acosh(3), asinh(3), atanh(3), ccos(3), sinh(3), tanh(3)
COLOPHON
This page is part of release 3.24 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/.
2008-08-10