.\" and Copyright 2008, Linux Foundation, written by Michael Kerrisk
.\" <mtk.manpages@gmail.com>
.\"
+.\" %%%LICENSE_START(VERBATIM)
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
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.\" References consulted:
.\" Linux libc source code
.\" Modified 2002-07-25 by Walter Harms
.\" (walter.harms@informatik.uni-oldenburg.de)
.\"
-.TH ACOS 3 2008-08-05 "" "Linux Programmer's Manual"
+.TH ACOS 3 2010-09-20 "" "Linux Programmer's Manual"
.SH NAME
acos, acosf, acosl \- arc cosine function
.SH SYNOPSIS
.ad l
.BR acosf (),
.BR acosl ():
-_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE; or
+.RS 4
+_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE ||
+_POSIX_C_SOURCE\ >=\ 200112L;
+.br
+or
.I cc\ -std=c99
+.RE
.ad b
.SH DESCRIPTION
The
.BR acos ()
-function calculates the arc cosine of \fIx\fP; that is
-the value whose cosine is \fIx\fP.
-.SH "RETURN VALUE"
+function calculates the arc cosine of
+.IR x ;
+that is
+the value whose cosine is
+.IR x .
+.SH RETURN VALUE
On success, these functions return the arc cosine of
.IR x
in radians; the return value is in the range [0,\ pi].
An invalid floating-point exception
.RB ( FE_INVALID )
is raised.
-.SH "CONFORMING TO"
+.SH CONFORMING TO
C99, POSIX.1-2001.
The variant returning
.I double
also conforms to
SVr4, 4.3BSD, C89.
-.SH "SEE ALSO"
+.SH SEE ALSO
.BR asin (3),
.BR atan (3),
.BR atan2 (3),
.BR cos (3),
.BR sin (3),
.BR tan (3)
+.SH COLOPHON
+This page is part of release 3.79 of the Linux
+.I man-pages
+project.
+A description of the project,
+information about reporting bugs,
+and the latest version of this page,
+can be found at
+\%http://www.kernel.org/doc/man\-pages/.