LDP
/
man-pages
mirror of https://github.com/mkerrisk/man-pages
0
1
Fork 0
Code Releases Activity

SYNOPSIS: Added feature test macro requirements. 

DESCRIPTION: Some rewording.
RETURN VALUE: Added details for special argument cases.
Added (null) ERRORS section.
Updated CONFORMING TO.
This commit is contained in:
Michael Kerrisk 2008-08-01 05:25:59 +00:00
parent 5ef3a12882
commit 9732b053bc
1 changed files with 43 additions and 14 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

57
man3/atan.3
View File

@ -1,4 +1,6 @@
.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk)
.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
.\" <mtk.manpages@gmail.com>
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
@ -28,7 +30,7 @@
.\" Modified 2002-07-27 by Walter Harms
.\" (walter.harms@informatik.uni-oldenburg.de)
.\"
.TH ATAN 3 2002-07-27 "" "Linux Programmer's Manual"
.TH ATAN 3 2008-07-29 "" "Linux Programmer's Manual"
.SH NAME
atan, atanf, atanl \- arc tangent function
.SH SYNOPSIS
@ -43,24 +45,51 @@ atan, atanf, atanl \- arc tangent function
.sp
.fi
Link with \fI\-lm\fP.
.sp
.in -4n
Feature Test Macro Requirements for glibc (see
.BR feature_test_macros (7)):
.in
.sp
.ad l
.BR atanf (),
.BR atanl ():
_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE; or
.I cc\ -std=c99
.ad b
.SH DESCRIPTION
The
.BR atan ()
function calculates the arc tangent of \fIx\fP; that is
the value whose tangent is \fIx\fP.
function calculates the principal value of the arc tangent of \fIx\fP;
that is the value whose tangent is \fIx\fP.
.SH "RETURN VALUE"
The
.BR atan ()
function returns the arc tangent in radians and the
value is mathematically defined to be between \-PI/2 and PI/2
(inclusive).
On success, these functions return the principal value of the arc tangent of
.IR x
in radians; the return value is in the range [\-pi/2,\ pi/2].
If
.I x
is a NaN, a NaN is returned.
If
.I x
is +0 (\-0),
+0 (\-0) is returned.
If
.I x
is positive infinity (negative infinity), +pi/2 (\-pi/2) is returned.
.\"
.\" POSIX.1-2001 documents an optional range error for subnormal x;
.\" glibc 2.8 does not do this.
.SH ERRORS
No errors occur.
.SH "CONFORMING TO"
SVr4, POSIX.1-2001, 4.3BSD, C89.
The
.I float
and
.I "long double"
variants are C99 requirements.
C99, POSIX.1-2001.
The variant returning
.I double
also conforms to
SVr4, 4.3BSD, C89.
.SH "SEE ALSO"
.BR acos (3),
.BR asin (3),