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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
     attributes(7).

     allbox;  lbw24  lb  lb  l  l  l.   Interface Attribute Value T{ cosh(),
     coshf(), coshl() T}   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.