/* @(#)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 <>, <>---arc cosine INDEX acos INDEX acosf ANSI_SYNOPSIS #include double acos(double <[x]>); float acosf(float <[x]>); TRAD_SYNOPSIS #include double acos(<[x]>) double <[x]>; float acosf(<[x]>) float <[x]>; DESCRIPTION <> computes the inverse cosine (arc cosine) of the input value. Arguments to <> must be in the range @minus{}1 to 1. <> is identical to <>, except that it performs its calculations on <>. RETURNS @ifinfo <> and <> return values in radians, in the range of 0 to pi. @end ifinfo @tex <> and <> 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 <> is set to <>, and a <> message is sent as standard error output. You can modify error handling for these functions using <>. 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 #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) */