COSH(3) Linux Programmer s Manual COSH(3)

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 3.22 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 COSH(3)