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COSH(3P)                   POSIX Programmer's Manual                  COSH(3P)

PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
NAME
       cosh, coshf, coshl - hyperbolic cosine functions
SYNOPSIS
       #include <math.h>
       double cosh(double x);
       float coshf(float x);
       long double coshl(long double x);

DESCRIPTION
       These functions shall compute the hyperbolic cosine of  their  argument
       x.
       An  application  wishing to check for error situations should set errno
       to zero and  call  feclearexcept(FE_ALL_EXCEPT)  before  calling  these
       functions.   On return, if errno is non-zero or fetestexcept(FE_INVALID
       | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is non-zero, an error  has
       occurred.
RETURN VALUE
       Upon successful completion, these functions shall return the hyperbolic
       cosine of x.
       If the correct value would cause overflow, a range  error  shall  occur
       and  cosh(),  coshf(),  and coshl() shall return the value of the macro
       HUGE_VAL, HUGE_VALF, and HUGE_VALL, respectively.
       If x is NaN, a NaN shall be returned.
       If x is +-0, the value 1.0 shall be returned.
       If x is +-Inf, +Inf shall be returned.
ERRORS
       These functions shall fail if:
       Range Error
              The result would cause an overflow.
       If the integer expression (math_errhandling & MATH_ERRNO) is  non-zero,
       then  errno  shall  be  set  to  [ERANGE].  If  the  integer expression
       (math_errhandling & MATH_ERREXCEPT)  is  non-zero,  then  the  overflow
       floating-point exception shall be raised.

       The following sections are informative.
EXAMPLES
       None.
APPLICATION USAGE
       On   error,   the   expressions  (math_errhandling  &  MATH_ERRNO)  and
       (math_errhandling & MATH_ERREXCEPT) are independent of each other,  but
       at least one of them must be non-zero.
       For  IEEE Std 754-1985  double,  710.5  < |x| implies that cosh( x) has
       overflowed.
RATIONALE
       None.
FUTURE DIRECTIONS
       None.
SEE ALSO
       acosh(), feclearexcept(), fetestexcept(), isnan(), sinh(), tanh(),  the
       Base  Definitions  volume of IEEE Std 1003.1-2001, Section 4.18, Treat-
       ment of Error Conditions for Mathematical Functions, <math.h>
COPYRIGHT
       Portions of this text are reprinted and reproduced in  electronic  form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       -- Portable Operating System Interface (POSIX),  The  Open  Group  Base
       Specifications  Issue  6,  Copyright  (C) 2001-2003 by the Institute of
       Electrical and Electronics Engineers, Inc and The Open  Group.  In  the
       event of any discrepancy between this version and the original IEEE and
       The Open Group Standard, the original IEEE and The Open Group  Standard
       is  the  referee document. The original Standard can be obtained online
       at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group                  2003                             COSH(3P)