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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) */
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