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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
+ @ifinfo
+ . (exp(x) + exp(-x))/2
+ @end ifinfo
+ @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) */