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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-15 19:40:15 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-15 19:40:15 +0000
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Adding upstream version 6.05.01.upstream/6.05.01
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+'\" 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)