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, respec-
       tively.

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 3.25 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)