Passing the repeatTime from ns2 to .cc file

Question

I am writing code for a simple simulation. We have 10 nodes and one sink node. I want to run the simulation for 5 times. The only thing I know so far is that I need to write set val(repeatTimes) 5, but I don't know how to use it in the simulation. Also, I add two lines of code as follow in the corresponding mac-simple.cc file in order to receive the repeat time from ns2. Then I compile the .cc file and run the simulation. However, when I run the .tcl file it shows me an error that it cannot find the repeatTimes variable.

Here are the two lines of code that I add under the function Mac():

tcl.evalf("Mac/Simple set repeatTimes");
bind("repeatTimes", &repeatTimes);

Do you the solution to this problem? If you don't know the solution, can you please guide me towards a forum/website where I can look for the solution?

Thanks in advance

Answer 1

Is the bind in your constructor for the class of the Mac/MncPrj object? (That's where it needs to be.) If so, it needs to be before the tcl.evalf call because it defines the variable from the perspective of OTcl; the code to read it won't work (and will generate a Tcl error — an exception in the Tcl level — if you try to do it) until after the binding has been done.

Once you've done the binding, you can read the variable from the Tcl script side with:

Mac/MncPrj set repeatTimes

and write it with:

Mac/MncPrj set repeatTimes $whateverTheValueIs

You should avoid keeping the value in a Tcl array; that'll be a non-live copy and will confuse you. (Unless you get much deeper into the magic of trace add variable, and that will definitely confuse you. It confuses me sometimes!)