COSH(3)                   (2017-09-15)                    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 func-
          tions  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

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     COSH(3)                   (2017-09-15)                    COSH(3)

               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.

     SEE ALSO
          acosh(3), asinh(3), atanh(3), ccos(3), sinh(3), tanh(3)

     COLOPHON
          This page is part of release 5.10  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/.

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