[Ns-developers] get value of a GlobalVariable

[Nicola Baldo]

I'm moving this to ns-dev since it has become a dev issue...


On Jul 2, 3:27 pm, Mathieu Lacage <mathieu.lac... at sophia.inria.fr> wrote:
> On Thu, 2009-07-02 at 14:48 +0200, Nicola Baldo wrote:
>> How can I get of the value of a GlobalVariable?
> 
>> Example: in the main() of my simulation, I need know the value of
>> RngRun which was passed to the command line. I am currently doing
>> it in the following way:
> 
>> #include "ns3/core-module.h"
> 
>> using namespace ns3;
> 
>> int main (int argc, char *argv[]) { CommandLine cmd; cmd.Parse
>> (argc, argv);
> 
>> int run; IntegerValue runValue; GlobalValue::Iterator gvit; 
>> for (gvit = GlobalValue::Begin (); gvit != GlobalValue::End ();
 >> ++gvit)
>> { if ((*gvit)->GetName () == "RngRun") { (*gvit)->GetValue
>> (runValue); run = runValue.Get (); } }
> 
>> std::cout<< "rngRun = " << run << std::endl;
> 
>> return 0; }
> 
>> Is there any nicer way to do it?
> 
> I don't think so but I guess we could add void 
> GlobalValue::GetValueByName (std::string name, AttributeValue
> &value). Care to cook a patch ?

Patch attached. If it is ok I can commit it to ns-3-dev.


> 
> Another nice thing would be to fix  bug
 > http://www.nsnam.org/bugzilla/show_bug.cgi?id=184

I'm sorry but I do not understand why this is related.


> 
> Are you aware that ns3::ConfigStore can be used to save/load a file
> (raw text or xml) which contains the value, among others, of the 
> RngRun/RngSeed global value ?

Yes that's cool, though poorly documented... a couple of weeks ago I was 
looking at it, but I couldn't find any example code, so it took me a 
while to figure it out how to use it!

Still, for this particular case I really needed to get the value within 
the sim program (I just wanted to name some pcap traces according to 
RngRun) so I do not see how ConfigStore could have been useful.


Nicola




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