Re: [ns] i'm very new with ns

["Marcos \"Locksmith\" Portnoi" <mportnoi@ieee.org>]

Hey, it looks like my code!! :))

Check whether sink0 was defined properly outside the record procedure, and
before it.  In my code, it is defined as
set sink0 [new Agent/LossMonitor]
$ns attach-agent $node $sink0

Portnoi
----- Original Message -----
From: "Raymond Wang" <rayw@stanford.edu>
To: <ns-users@ISI.EDU>
Sent: Saturday, 29 de September de 2001 02:26
Subject: [ns] i'm very new with ns


> hi,
>
> i'm very new with ns.  here is a snippet of my code (actually borrowed
from
> someone with permission and i'm trying to understand it), why does it
> result in the errors below?
>
> thanks a lot!
> ray
>
> proc record {} {
>          global sink0 f0
>          #Get an instance of the simulator
>          set ns [Simulator instance]
>          #Set the time after which the procedure should be called again
>          set time 0.5
>          #How many bytes have been received by the traffic sinks?
>          set bw0 [$sink0 set bytes_]
>          #Get the current time
>          set now [$ns now]
>          #Calculate the bandwidth (in MBit/s) and write it to the files
>          puts $f0 "$now [expr $bw0/$time*8/1000000]"
>          #Reset the bytes_ values on the traffic sinks
>          $sink0 set bytes_ 0
>          #Re-schedule the procedure
>          $ns at [expr $now+$time] "record"
> }
>
> Errors:
> ns: record: can't read "bytes_": no such variable
>      while executing
> "subst $[subst $var"
>      (procedure "_o44" line 5)
>      (Object next line 5)
>      invoked from within
> "_o44 next bytes_"
>      ("eval" body line 1)
>      invoked from within
> "eval $self next $args"
>      (procedure "_o44" line 18)
>      (Agent set line 18)
>      invoked from within
> "$sink0 set bytes_"
>      (procedure "record" line 8)
>      invoked from within
> "record"
>
>
>