diff options
Diffstat (limited to 'man3/atan2.3')
| -rw-r--r-- | man3/atan2.3 | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/man3/atan2.3 b/man3/atan2.3 new file mode 100644 index 0000000..0532b47 --- /dev/null +++ b/man3/atan2.3 @@ -0,0 +1,175 @@ +'\" t +.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) +.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk +.\" <mtk.manpages@gmail.com> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.\" 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 (faith@cs.unc.edu) +.\" Modified 2002-07-27 by Walter Harms +.\" (walter.harms@informatik.uni-oldenburg.de) +.\" +.TH atan2 3 2023-07-20 "Linux man-pages 6.05.01" +.SH NAME +atan2, atan2f, atan2l \- arc tangent function of two variables +.SH LIBRARY +Math library +.RI ( libm ", " \-lm ) +.SH SYNOPSIS +.nf +.B #include <math.h> +.PP +.BI "double atan2(double " y ", double " x ); +.BI "float atan2f(float " y ", float " x ); +.BI "long double atan2l(long double " y ", long double " x ); +.fi +.PP +.RS -4 +Feature Test Macro Requirements for glibc (see +.BR feature_test_macros (7)): +.RE +.PP +.BR atan2f (), +.BR atan2l (): +.nf + _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L + || /* Since glibc 2.19: */ _DEFAULT_SOURCE + || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE +.fi +.SH DESCRIPTION +These functions calculate the principal value of the arc tangent of +.IR y/x , +using the signs of the two arguments to determine +the quadrant of the result. +.SH RETURN VALUE +On success, these functions return the principal value of the arc tangent of +.I y/x +in radians; the return value is in the range [\-pi,\ pi]. +.PP +If +.I y +is +0 (\-0) and +.I x +is less than 0, +pi (\-pi) is returned. +.PP +If +.I y +is +0 (\-0) and +.I x +is greater than 0, +0 (\-0) is returned. +.PP +If +.I y +is less than 0 and +.I x +is +0 or \-0, \-pi/2 is returned. +.PP +If +.I y +is greater than 0 and +.I x +is +0 or \-0, pi/2 is returned. +.PP +.\" POSIX.1 says: +.\" If +.\" .I x +.\" is 0, a pole error shall not occur. +.\" +If either +.I x +or +.I y +is NaN, a NaN is returned. +.PP +.\" POSIX.1 says: +.\" If the result underflows, a range error may occur and +.\" .I y/x +.\" should be returned. +.\" +If +.I y +is +0 (\-0) and +.I x +is \-0, +pi (\-pi) is returned. +.PP +If +.I y +is +0 (\-0) and +.I x +is +0, +0 (\-0) is returned. +.PP +If +.I y +is a finite value greater (less) than 0, and +.I x +is negative infinity, +pi (\-pi) is returned. +.PP +If +.I y +is a finite value greater (less) than 0, and +.I x +is positive infinity, +0 (\-0) is returned. +.PP +If +.I y +is positive infinity (negative infinity), and +.I x +is finite, +pi/2 (\-pi/2) is returned. +.PP +If +.I y +is positive infinity (negative infinity) and +.I x +is negative infinity, +3*pi/4 (\-3*pi/4) is returned. +.PP +If +.I y +is positive infinity (negative infinity) and +.I x +is positive infinity, +pi/4 (\-pi/4) is returned. +.\" +.\" POSIX.1 says: +.\" If both arguments are 0, a domain error shall not occur. +.SH ERRORS +No errors occur. +.\" POSIX.1 documents an optional underflow error +.\" glibc 2.8 does not do this. +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR atan2 (), +.BR atan2f (), +.BR atan2l () +T} Thread safety MT-Safe +.TE +.sp 1 +.SH STANDARDS +C11, POSIX.1-2008. +.SH HISTORY +C99, POSIX.1-2001. +.PP +The variant returning +.I double +also conforms to +SVr4, 4.3BSD, C89. +.SH SEE ALSO +.BR acos (3), +.BR asin (3), +.BR atan (3), +.BR carg (3), +.BR cos (3), +.BR sin (3), +.BR tan (3) |