Dear friends, I am reading chapter 13 of the book "Introduction to ns2" about trace in ns2. As I know, the TclObject class keeps a variable of type InstVar* to a list of InstVar objects in order to trace. The InstVar has three variables tracedvar_, name_ and next_. name_ and next_ are clear in purpose, tracedvar_ acts as a pointer to a TracedVar object. So I understand that the purpose of InstVar is to trace variables of TclObject. If tracedvar_ can be null, what is the purpose of InstVar now?
Hieu Nguyen