mirror of https://github.com/mkerrisk/man-pages
64 lines
2.3 KiB
Groff
64 lines
2.3 KiB
Groff
.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
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.\"
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.\" Permission is granted to make and distribute verbatim copies of this
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.\" manual provided the copyright notice and this permission notice are
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.\" preserved on all copies.
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.\"
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.\" Permission is granted to copy and distribute modified versions of this
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.\" manual under the conditions for verbatim copying, provided that the
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.\" entire resulting derived work is distributed under the terms of a
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.\" permission notice identical to this one.
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.\"
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.\" Since the Linux kernel and libraries are constantly changing, this
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.\" manual page may be incorrect or out-of-date. The author(s) assume no
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.\" responsibility for errors or omissions, or for damages resulting from
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.\" the use of the information contained herein. The author(s) may not
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.\" have taken the same level of care in the production of this manual,
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.\" which is licensed free of charge, as they might when working
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.\" professionally.
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.\"
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.\" Formatted or processed versions of this manual, if unaccompanied by
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.\" the source, must acknowledge the copyright and authors of this work.
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.\"
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.\" References consulted:
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.\" Linux libc source code
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.\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
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.\" 386BSD man pages
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.\" Modified 1993-07-24 by Rik Faith (faith@cs.unc.edu)
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.\" Modified 2002-07-27 by Walter Harms
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.\" (walter.harms@informatik.uni-oldenburg.de)
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.\"
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.TH ATAN2 3 2002-07-27 "" "Linux Programmer's Manual"
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.SH NAME
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atan2, atan2f, atan2l \- arc tangent function of two variables
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.SH SYNOPSIS
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.nf
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.B #include <math.h>
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.sp
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.BI "double atan2(double " y ", double " x );
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.br
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.BI "float atan2f(float " y ", float " x );
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.br
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.BI "long double atan2l(long double " y ", long double " x );
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.sp
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.fi
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Link with \-lm.
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.SH DESCRIPTION
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The \fBatan2\fP() function calculates the arc tangent of the two
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variables \fIx\fP and \fIy\fP. It is similar to calculating the
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arc tangent of \fIy\fP / \fIx\fP, except that the signs of both
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arguments are used to determine the quadrant of the result.
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.SH "RETURN VALUE"
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The \fBatan2\fP() function returns the result in radians, which
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is between \-PI and PI (inclusive).
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.SH "CONFORMING TO"
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SVr4, POSIX.1-2001, 4.3BSD, C89.
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The float and long double variants are C99 requirements.
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.SH "SEE ALSO"
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.BR acos (3),
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.BR asin (3),
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.BR atan (3),
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.BR cos (3),
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.BR sin (3),
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.BR tan (3)
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