/* @(#)w_atan2.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 <<atan2>>, <<atan2f>>---arc tangent of y/x INDEX atan2 INDEX atan2f ANSI_SYNOPSIS #include <math.h> double atan2(double <[y]>,double <[x]>); float atan2f(float <[y]>,float <[x]>); TRAD_SYNOPSIS #include <math.h> double atan2(<[y]>,<[x]>); double <[y]>; double <[x]>; float atan2f(<[y]>,<[x]>); float <[y]>; float <[x]>; DESCRIPTION <<atan2>> computes the inverse tangent (arc tangent) of <[y]>/<[x]>. <<atan2>> produces the correct result even for angles near @ifnottex pi/2 or -pi/2 @end ifnottex @tex $\pi/2$ or $-\pi/2$ @end tex (that is, when <[x]> is near 0). <<atan2f>> is identical to <<atan2>>, save that it takes and returns <<float>>. RETURNS <<atan2>> and <<atan2f>> return a value in radians, in the range of @ifnottex -pi to pi. @end ifnottex @tex $-\pi$ to $\pi$. @end tex You can modify error handling for these functions using <<matherr>>. PORTABILITY <<atan2>> is ANSI C. <<atan2f>> is an extension. */ /* * wrapper atan2(y,x) */ #include "fdlibm.h" #include <errno.h> #ifndef _DOUBLE_IS_32BITS #ifdef __STDC__ double atan2(double y, double x) /* wrapper atan2 */ #else double atan2(y,x) /* wrapper atan2 */ double y,x; #endif { return __ieee754_atan2(y,x); } #endif /* defined(_DOUBLE_IS_32BITS) */