Added example

1 files changed, 11 insertions, 3 deletions

diff --git a/doc/upvar.n b/doc/upvar.n
index 84399c7..bb25fee 100644
--- a/doc/upvar.n
+++ b/doc/upvar.n
@@ -5,7 +5,7 @@
 '\" See the file "license.terms" for information on usage and redistribution
 '\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
 '\" 
-'\" RCS: @(#) $Id: upvar.n,v 1.6 2004/04/28 13:11:33 msofer Exp $
+'\" RCS: @(#) $Id: upvar.n,v 1.7 2004/05/18 21:29:22 dkf Exp $
 '\" 
 .so man.macros
 .TH upvar n "" Tcl "Tcl Built-In Commands"
@@ -75,8 +75,7 @@ upvar variable.  There is no way to unset an upvar variable except
 by exiting the procedure in which it is defined.  However, it is
 possible to retarget an upvar variable by executing another \fBupvar\fR
 command.
-
-.SH Traces and upvar
+.SH "TRACES AND UPVAR"
 .PP
 Upvar interacts with traces in a straightforward but possibly
 unexpected manner.  If a variable trace is defined on \fIotherVar\fR, that
@@ -104,6 +103,15 @@ is accessed (but traces on the particular element will still be
 invoked).  In particular, if the array is \fBenv\fR, then changes
 made to \fImyVar\fR will not be passed to subprocesses correctly.
 .VE
+.SH EXAMPLE
+A \fBdecr\fR command that works like \fBincr\fR except it subtracts
+the value from the variable instead of adding it:
+.CS
+proc decr {varName {decrement 1}} {
+    upvar 1 $varName var
+    incr var [expr {-$decrement}]
+}
+.CE
 
 .SH "SEE ALSO"
 global(n), namespace(n), uplevel(n), variable(n)