SYNOPSIS: Added feature test macro requirements.

Added RETURN VALUE section.
Added (null) ERRORS section.
Updated CONFORMING TO.

diff --git a/man3/tanh.3 b/man3/tanh.3
index e05b1dcd26b07fc99fd7dd17017a7c9b8e50c62e..cc9f41ad838c0ae4e57cc92ffb1c4388de8e54e0 100644 (file)
--- a/man3/tanh.3
+++ b/man3/tanh.3
@@ -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 TANH 3 2007-12-26 ""  "Linux Programmer's Manual"
+.TH TANH 3 2008-07-29 ""  "Linux Programmer's Manual"
 .SH NAME
 tanh, tanhf, tanhl \- hyperbolic tangent function
 .SH SYNOPSIS
@@ -43,6 +45,18 @@ tanh, tanhf, tanhl \- hyperbolic tangent function
 .fi
 .sp
 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 tanhf (),
+.BR tanhl ():
+_BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE\ >=\ 600 || _ISOC99_SOURCE; or
+.I cc\ -std=c99
+.ad b
 .SH DESCRIPTION
 The
 .BR tanh ()
@@ -52,13 +66,34 @@ is defined mathematically as:
 
     tanh(x) = sinh(x) / cosh(x)
 .fi
+.SH "RETURN VALUE"
+On success, these functions return the hyperbolic tangent of
+.IR x .
+
+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),
++1 (\-1) is returned.
+.\"
+.\" POSIX.1-2001 documents an optional range error (underflow) 
+.\" for subnormal x;
+.\" glibc 2.8 does not do this.
+.SH ERRORS
+No errors occur.
 .SH "CONFORMING TO"
+C99, POSIX.1-2001.
+The variant returning
+.I double
+also conforms to
 SVr4, 4.3BSD, C89.
-The
-.I float
-and
-.I "long double"
-variants are C99 requirements.
 .SH "SEE ALSO"
 .BR acosh (3),
 .BR asinh (3),