[ns] Question about get-link-head error.

[Sun Weiqiang]

hi All,

	I did the following to define a node:
	
in C++:
     DWDMNodeClass() : TclClass("Node/DWDM") {}

in tcl:
	Node/DWDM instproc init args {
		eval $self next $args
		#...
	}

	Simulator instproc RWAnode args {
		$self instvar linked_DWDMnodes_
	
		set tmp [Simulator set node_factory_]
	
		Simulator set node_factory_ Node/DWDM
		set n [$self node]
		lappend linked_DWDMnodes_ $n
	
		Simulator set node_factory_ $tmp

		return $n
	}

and in my simulation scripts:
	set ns [new Simulator]
	set n1 [$ns RWAnode]
	set n2 [$ns RWAnode]	

I can see that my c++ code was put into the class hierarchy, 
but when I do the routing staff on such nodes, I got the following error:

$ns rtproto DV
$ns compute-routes

ns: [Simulator instance] get-link-head -1 1: can't read "link_(-1:1)": no such element in array
    while executing
"$link_($n1:$n2) head"
    (procedure "_o4" line 3)
    (Simulator get-link-head line 3)
    invoked from within
"[Simulator instance] get-link-head -1 1"

It seems that something wrong with the hash value of such node objects when handled by tcl
(ie. Tcl_CreateHashEntry and Tcl_SetHashValue).

What should I  do to solve this problem?

Thank you for your time,

Weiqiang