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/* @(#)w_cosh.c 5.1 93/09/24 */

/*

 * ====================================================

 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.

 *

 * Developed at SunPro, a Sun Microsystems, Inc. business.

 * Permission to use, copy, modify, and distribute this

 * software is freely granted, provided that this notice

 * is preserved.

 * ====================================================

 */

/*

FUNCTION

        <<cosh>>, <<coshf>>---hyperbolic cosine

ANSI_SYNOPSIS

        #include <math.h>

        double cosh(double <[x]>);

        float coshf(float <[x]>)

TRAD_SYNOPSIS

        #include <math.h>

        double cosh(<[x]>)

        double <[x]>;

        float coshf(<[x]>)

        float <[x]>;

DESCRIPTION

        <<cosh>> computes the hyperbolic cosine of the argument <[x]>.

        <<cosh(<[x]>)>> is defined as

        @ifnottex

        . (exp(x) + exp(-x))/2

        @end ifnottex

        @tex

        $${(e^x + e^{-x})} \over 2$$

        @end tex

        Angles are specified in radians.

        <<coshf>> is identical, save that it takes and returns <<float>>.

RETURNS

        The computed value is returned.  When the correct value would create

        an overflow,  <<cosh>> returns the value <<HUGE_VAL>> with the

        appropriate sign, and the global value <<errno>> is set to <<ERANGE>>.

        You can modify error handling for these functions using the

        function <<matherr>>.

PORTABILITY

        <<cosh>> is ANSI.

        <<coshf>> is an extension.

QUICKREF

        cosh ansi pure

        coshf - pure

*/

/*

 * wrapper cosh(x)

 */

#include "fdlibm.h"

#include <errno.h>

#ifndef _DOUBLE_IS_32BITS

#ifdef __STDC__

        double cosh(double x)           /* wrapper cosh */

#else

        double cosh(x)                  /* wrapper cosh */

        double x;

#endif

{

#ifdef _IEEE_LIBM

        return __ieee754_cosh(x);

#else

        double z;

        struct exception exc;

        z = __ieee754_cosh(x);

        if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;

        if(fabs(x)>7.10475860073943863426e+02) {

            /* cosh(finite) overflow */

#ifndef HUGE_VAL

#define HUGE_VAL inf

            double inf = 0.0;

            SET_HIGH_WORD(inf,0x7ff00000);      /* set inf to infinite */

#endif

            exc.type = OVERFLOW;

            exc.name = "cosh";

            exc.err = 0;

            exc.arg1 = exc.arg2 = x;

            if (_LIB_VERSION == _SVID_)

               exc.retval = HUGE;

            else

               exc.retval = HUGE_VAL;

            if (_LIB_VERSION == _POSIX_)

               errno = ERANGE;

            else if (!matherr(&exc)) {

               errno = ERANGE;

            }

            if (exc.err != 0)

               errno = exc.err;

            return exc.retval;

        } else

            return z;

#endif

}

#endif /* defined(_DOUBLE_IS_32BITS) */