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+
+/* @(#)w_acos.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
+ <<acos>>, <<acosf>>---arc cosine
+
+INDEX
+ acos
+INDEX
+ acosf
+
+ANSI_SYNOPSIS
+ #include <math.h>
+ double acos(double <[x]>);
+ float acosf(float <[x]>);
+
+TRAD_SYNOPSIS
+ #include <math.h>
+ double acos(<[x]>)
+ double <[x]>;
+
+ float acosf(<[x]>)
+ float <[x]>;
+
+
+
+DESCRIPTION
+
+ <<acos>> computes the inverse cosine (arc cosine) of the input value.
+ Arguments to <<acos>> must be in the range @minus{}1 to 1.
+
+ <<acosf>> is identical to <<acos>>, except that it performs
+ its calculations on <<floats>>.
+
+RETURNS
+ @ifinfo
+ <<acos>> and <<acosf>> return values in radians, in the range of 0 to pi.
+ @end ifinfo
+ @tex
+ <<acos>> and <<acosf>> return values in radians, in the range of <<0>> to $\pi$.
+ @end tex
+
+ If <[x]> is not between @minus{}1 and 1, the returned value is NaN
+ (not a number) the global variable <<errno>> is set to <<EDOM>>, and a
+ <<DOMAIN error>> message is sent as standard error output.
+
+ You can modify error handling for these functions using <<matherr>>.
+
+
+QUICKREF ANSI SVID POSIX RENTRANT
+ acos y,y,y,m
+ acosf n,n,n,m
+
+MATHREF
+ acos, [-1,1], acos(arg),,,
+ acos, NAN, arg,DOMAIN,EDOM
+
+MATHREF
+ acosf, [-1,1], acosf(arg),,,
+ acosf, NAN, argf,DOMAIN,EDOM
+
+*/
+
+/*
+ * wrap_acos(x)
+ */
+
+#include "fdlibm.h"
+#include <errno.h>
+
+#ifndef _DOUBLE_IS_32BITS
+
+#ifdef __STDC__
+ double acos(double x) /* wrapper acos */
+#else
+ double acos(x) /* wrapper acos */
+ double x;
+#endif
+{
+#ifdef _IEEE_LIBM
+ return __ieee754_acos(x);
+#else
+ double z;
+ struct exception exc;
+ z = __ieee754_acos(x);
+ if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
+ if(fabs(x)>1.0) {
+ /* acos(|x|>1) */
+ exc.type = DOMAIN;
+ exc.name = "acos";
+ exc.err = 0;
+ exc.arg1 = exc.arg2 = x;
+ exc.retval = 0.0;
+ if (_LIB_VERSION == _POSIX_)
+ errno = EDOM;
+ else if (!matherr(&exc)) {
+ errno = EDOM;
+ }
+ if (exc.err != 0)
+ errno = exc.err;
+ return exc.retval;
+ } else
+ return z;
+#endif
+}
+
+#endif /* defined(_DOUBLE_IS_32BITS) */