Omnet++: unknown parameter. Cannot use module parameters in simulations

Question

So I'm trying create a simple simulation in omnetpp, and I am having trouble with module parameters.

I have provided a simple example to demonstrate my problem. If I leave the commented sections in all the code commented, the simulation runs fine. If I un-comment the commented sections in all the code, my program compiles fine, but the simulation won't run. The debug output prints the following message:

Error in module (omnetpp::cModule) net (id=1) during network setup: (transceiver): unknown parameter `what'.

I don't know what the issue is, since 'what' is defined in my .ini file and my .ned. Here is my code:

transceiver.cc

#include <omnetpp.h>

using namespace omnetpp;


class transceiver : public cSimpleModule
{

    private:
        //int what;

    public:
        transceiver();
        virtual ~transceiver();

    protected:
        virtual void initialize() override;
        virtual void handleMessage(cMessage* msg) override;
};

Define_Module(transceiver);

transceiver::transceiver() {
    //what = par("what");
}

transceiver::~transceiver() {

}

void transceiver::initialize() {
    cMessage* msg = new cMessage("Message");
    send(msg, "out");
}

void transceiver::handleMessage(cMessage* msg) {
    EV << "We got a message!" << endl;
    delete msg;
}

package.ned

package packetgenerator;

@license(omnetpp);

omnetpp.ini

[General]
network = transceiver.net
#net.transceiver.what = 5

transceiver.ned

package transceiver;

simple transceiver
{
    parameters:
        //int what = default(2);
    gates:
        input in;
        output out;
}


network net
{
    submodules:
        transceiver: transceiver;
    connections:
        transceiver.out --> transceiver.in;
}

If it helps, the function call for findPar() within the function par() returns -1, meaning that the parameters don't exist. I thought I defined them in my .ini file and .ned file though. — Razorfoot

Rudi Rudi · Accepted Answer · 2016-09-13T11:51:59

You are NOT supposed to access parameters in the constructor of the module. Parameters should be accessed in the initalize() method.

Use

transceiver::initialize(int stage) {
    what = par("what");
}

instead of

transceiver::transceiver() {
    what = par("what");
}

Omnet++: unknown parameter. Cannot use module parameters in simulations

1 Answers