]>
Commit | Line | Data |
---|---|---|
fea681da MK |
1 | .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
2 | .\" | |
3 | .\" Permission is granted to make and distribute verbatim copies of this | |
4 | .\" manual provided the copyright notice and this permission notice are | |
5 | .\" preserved on all copies. | |
6 | .\" | |
7 | .\" Permission is granted to copy and distribute modified versions of this | |
8 | .\" manual under the conditions for verbatim copying, provided that the | |
9 | .\" entire resulting derived work is distributed under the terms of a | |
10 | .\" permission notice identical to this one. | |
c13182ef | 11 | .\" |
fea681da MK |
12 | .\" Since the Linux kernel and libraries are constantly changing, this |
13 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
14 | .\" responsibility for errors or omissions, or for damages resulting from | |
15 | .\" the use of the information contained herein. The author(s) may not | |
16 | .\" have taken the same level of care in the production of this manual, | |
17 | .\" which is licensed free of charge, as they might when working | |
18 | .\" professionally. | |
c13182ef | 19 | .\" |
fea681da MK |
20 | .\" Formatted or processed versions of this manual, if unaccompanied by |
21 | .\" the source, must acknowledge the copyright and authors of this work. | |
22 | .\" | |
23 | .\" References consulted: | |
24 | .\" Linux libc source code | |
25 | .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) | |
26 | .\" 386BSD man pages | |
27 | .\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu) | |
28 | .\" Modified 2002-07-27 by Walter Harms | |
29 | .\" (walter.harms@informatik.uni-oldenburg.de) | |
30 | .\" | |
31 | .TH ATAN2 3 2002-07-27 "" "Linux Programmer's Manual" | |
32 | .SH NAME | |
33 | atan2, atan2f, atan2l \- arc tangent function of two variables | |
34 | .SH SYNOPSIS | |
35 | .nf | |
36 | .B #include <math.h> | |
37 | .sp | |
38 | .BI "double atan2(double " y ", double " x ); | |
d39541ec | 39 | .br |
fea681da | 40 | .BI "float atan2f(float " y ", float " x ); |
d39541ec | 41 | .br |
fea681da | 42 | .BI "long double atan2l(long double " y ", long double " x ); |
c13182ef | 43 | .sp |
fea681da | 44 | .fi |
20c58d70 | 45 | Link with \fI\-lm\fP. |
fea681da | 46 | .SH DESCRIPTION |
60a90ecd MK |
47 | The |
48 | .BR atan2 () | |
49 | function calculates the arc tangent of the two | |
1c44bd5b MK |
50 | variables \fIx\fP and \fIy\fP. |
51 | It is similar to calculating the | |
646b2977 | 52 | arc tangent of \fIy\ /\ x\fP, except that the signs of both |
fea681da MK |
53 | arguments are used to determine the quadrant of the result. |
54 | .SH "RETURN VALUE" | |
60a90ecd MK |
55 | The |
56 | .BR atan2 () | |
57 | function returns the result in radians, which | |
4d9b6984 | 58 | is between \-PI and PI (inclusive). |
fea681da | 59 | .SH "CONFORMING TO" |
68e1685c | 60 | SVr4, POSIX.1-2001, 4.3BSD, C89. |
c13182ef | 61 | The |
9d9dc1e8 MK |
62 | .I float |
63 | and | |
64 | .I "long double" | |
65 | variants are C99 requirements. | |
fea681da MK |
66 | .SH "SEE ALSO" |
67 | .BR acos (3), | |
68 | .BR asin (3), | |
69 | .BR atan (3), | |
70 | .BR cos (3), | |
71 | .BR sin (3), | |
72 | .BR tan (3) |