cosh

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():
           _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
               || /* Since glibc 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION
       These  functions  return  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.

ATTRIBUTES
       For an  explanation  of  the  terms  used  in  this  section,  see  at-
       tributes(7).

       +-------------------------+---------------+---------+
       |Interface                | Attribute     | Value   |
       +-------------------------+---------------+---------+
       |cosh(), coshf(), coshl() | Thread safety | MT-Safe |
       +-------------------------+---------------+---------+
CONFORMING TO
       C99, POSIX.1-2001, POSIX.1-2008.

       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 5.05 of the Linux  man-pages  project.   A
       description  of  the project, information about reporting bugs, and the
       latest    version    of    this    page,    can     be     found     at
       https://www.kernel.org/doc/man-pages/.

                                  2017-09-15                           COSH(3)