Copy from the is* manpages the CAVEAT about the input range.

ok jmc@

2 files changed, 20 insertions, 4 deletions

diff --git a/lib/libc/gen/tolower.3 b/lib/libc/gen/tolower.3
index e2b2f8ad95c..77ed3a287ae 100644
--- a/lib/libc/gen/tolower.3
+++ b/lib/libc/gen/tolower.3
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: tolower.3,v 1.11 2007/05/31 19:19:29 jmc Exp $
+.\"	$OpenBSD: tolower.3,v 1.12 2012/11/23 22:54:08 guenther Exp $
 .\"
 .\" Copyright (c) 1989, 1991 The Regents of the University of California.
 .\" All rights reserved.
@@ -31,7 +31,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: May 31 2007 $
+.Dd $Mdocdate: November 23 2012 $
 .Dt TOLOWER 3
 .Os
 .Sh NAME
@@ -99,3 +99,11 @@ and
 .Fn _tolower
 functions conform to
 .St -ansiC .
+.Sh CAVEATS
+The argument to
+.Nm
+must be
+.Dv EOF
+or representable as an
+.Li unsigned char ;
+otherwise, the result is undefined.
diff --git a/lib/libc/gen/toupper.3 b/lib/libc/gen/toupper.3
index 62cd690c7e7..5eae1357300 100644
--- a/lib/libc/gen/toupper.3
+++ b/lib/libc/gen/toupper.3
@@ -1,4 +1,4 @@
-.\"	$OpenBSD: toupper.3,v 1.13 2007/05/31 19:19:29 jmc Exp $
+.\"	$OpenBSD: toupper.3,v 1.14 2012/11/23 22:54:08 guenther Exp $
 .\"
 .\" Copyright (c) 1989, 1991 The Regents of the University of California.
 .\" All rights reserved.
@@ -31,7 +31,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd $Mdocdate: May 31 2007 $
+.Dd $Mdocdate: November 23 2012 $
 .Dt TOUPPER 3
 .Os
 .Sh NAME
@@ -97,3 +97,11 @@ The
 .Fn toupper
 function conforms to
 .St -ansiC .
+.Sh CAVEATS
+The argument to
+.Nm
+must be
+.Dv EOF
+or representable as an
+.Li unsigned char ;
+otherwise, the result is undefined.