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120 lines
2.5 KiB
C
120 lines
2.5 KiB
C
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/* @(#)w_acos.c 5.1 93/09/24 */
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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/*
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FUNCTION
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<<acos>>, <<acosf>>---arc cosine
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INDEX
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acos
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INDEX
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acosf
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ANSI_SYNOPSIS
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#include <math.h>
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double acos(double <[x]>);
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float acosf(float <[x]>);
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TRAD_SYNOPSIS
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#include <math.h>
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double acos(<[x]>)
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double <[x]>;
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float acosf(<[x]>)
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float <[x]>;
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DESCRIPTION
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<<acos>> computes the inverse cosine (arc cosine) of the input value.
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Arguments to <<acos>> must be in the range @minus{}1 to 1.
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<<acosf>> is identical to <<acos>>, except that it performs
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its calculations on <<floats>>.
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RETURNS
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@ifnottex
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<<acos>> and <<acosf>> return values in radians, in the range of 0 to pi.
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@end ifnottex
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@tex
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<<acos>> and <<acosf>> return values in radians, in the range of <<0>> to $\pi$.
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@end tex
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If <[x]> is not between @minus{}1 and 1, the returned value is NaN
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(not a number) the global variable <<errno>> is set to <<EDOM>>, and a
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<<DOMAIN error>> message is sent as standard error output.
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You can modify error handling for these functions using <<matherr>>.
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QUICKREF
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ansi svid posix rentrant
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acos y,y,y,m
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acosf n,n,n,m
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MATHREF
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acos, [-1,1], acos(arg),,,
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acos, NAN, arg,DOMAIN,EDOM
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MATHREF
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acosf, [-1,1], acosf(arg),,,
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acosf, NAN, argf,DOMAIN,EDOM
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*/
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/*
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* wrap_acos(x)
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*/
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#include "fdlibm.h"
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#include <errno.h>
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#ifndef _DOUBLE_IS_32BITS
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#ifdef __STDC__
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double acos(double x) /* wrapper acos */
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#else
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double acos(x) /* wrapper acos */
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double x;
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#endif
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{
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#ifdef _IEEE_LIBM
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return __ieee754_acos(x);
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#else
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double z;
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struct exception exc;
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z = __ieee754_acos(x);
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if(_LIB_VERSION == _IEEE_ || isnan(x)) return z;
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if(fabs(x)>1.0) {
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/* acos(|x|>1) */
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exc.type = DOMAIN;
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exc.name = "acos";
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exc.err = 0;
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exc.arg1 = exc.arg2 = x;
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exc.retval = nan("");
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if (_LIB_VERSION == _POSIX_)
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errno = EDOM;
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else if (!matherr(&exc)) {
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errno = EDOM;
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}
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if (exc.err != 0)
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errno = exc.err;
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return exc.retval;
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} else
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return z;
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#endif
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}
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#endif /* defined(_DOUBLE_IS_32BITS) */
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