Name
atan2, atan2f, atan2l — arc tangent function of two variables
Synopsis
#include <math.h>
double atan2( |
double | y, |
| double | x); |
float
atan2f( |
float | y, |
| float | x); |
long
double atan2l( |
long double | y, |
| long double | x); |
![[Note]](../stylesheet/note.png) |
Note |
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Link with |
DESCRIPTION
The atan2() function
calculates the arc tangent of the two variables x and y. It is similar to calculating
the arc tangent of y /
x, except that the signs of both arguments are
used to determine the quadrant of the result.
RETURN VALUE
The atan2() function returns
the result in radians, which is between −PI and PI
(inclusive).
CONFORMING TO
SVr4, POSIX.1-2001, 4.3BSD, C89. The float and long double variants are C99 requirements.
COLOPHON
This page is part of release 2.79 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at
http://www.kernel.org/doc/man-pages/.
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Copyright 1993 David Metcalfe (davidprism.demon.co.uk) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. References consulted: Linux libc source code Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) 386BSD man pages Modified 1993-07-24 by Rik Faith (faithcs.unc.edu) Modified 2002-07-27 by Walter Harms (walter.harmsinformatik.uni-oldenburg.de) |