Question

I’m new to using CORBA and I’m struggling with correctly passing the parameters to a method that I want to invoke. The method has the IDL signature

void addUpdateListener(out OpStatus opStatus, in IPlanningUpdateListener listener);

OpStatus is a struct defined as

struct OpStatus {
    EComponent EComp;
    EStatus State;
    string Message;
}
enum EComponent { CompA, CompB, CompC };
enum EStatus { SUCCESS, FAILURE, RETRY };

and IPlanningUpdateListener is itself an IDL interface.

I’ve implemented the _impl of the class looks like

void addUpdateListener(OpStatus_out opStatus, _objref_IPlanningUpdateListener* listener)    {
    std::cout << "addUpdateListener called\n";
}

I’ve managed to register all my services with the ORB correctly and but I don’t know how to actually call this method. I’ve got a pointer to the service that I want to be added as a listener but it’s not of the correct type. Does anyone know why omniidl converts the existing OpStatus and IPlanningUpdateListener types in the IDL into the new OpStatus_out and _objref_IPlanningUpdateListener types. I thought for out parameters all I needed to do was pass a reference.

IPlanningUpdateListener_impl* listener // initialised and registered earlier
OpStatus opStatus; 
myClass->addUpdateListener(opStatus, listener);

My two questions are how do I get this method to accept my implementation of the IPlanningUpdateListener as a parameter and what do I need to do to convert the OpStatus struct into the OpStatus_out type that the omniidl has created?

Answer 1

In the client change OpStatus to a _var.

OpStatus_var opStatus; 
myClass->addUpdateListener(opStatus, listener);

The implementation will create a new struct to return.

void addUpdateListener(OpStatus_out opStatus, _objref_IPlanningUpdateListener* listener)    
{
  opStats = new OpStatus;

...
}