| |
| /* @(#)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) */ |
