Passing a class pointer to a method call

ROOT
1

Hi,
I’ve got a “dynamic” interface implemented to ROOT - so I can create objects (minus the ctor implementation referenced in another question) and then call the methods on it. Works well. One big limitation currently is if a method needs an argument to another class. For example. TH1::Divide, which takes another TH1* as an argument.

I’ve been using TMethodCall::Execute to tell CINT to do the call. And I pass the arguments as a string. For example, say I have some code similar to below (sorry, it isn’t totally right):

  TH1F *h1 = ...
  TH1F *h2 = ...
  TMethodCall method;
  method.InitWithPrototype(TClass::GetClass("TH1F"), "Divide", "TH1F");
  method.Execute(h1, ???);

I tried soemthing dumb, like

  ostringstream args;
  args << h2;
  method.Execute(h1, args.str().c_str());

but the access violation was impressive. Is this a limitation of TMethodCall? Perhaps I should use CINT directly somehow (as pyroot seems to do)?

2

Can you, please, explain, why do you want replace traditional C++ syntax with some function calls?
Do you have to use C++ (ROOT classes) from other language?

3

Hi,
Sorry, I should have updated this question. I’m trying to implement pyROOT’s functionality for the .NET world. I was thinking, after reading through ROOT documentation, I didn’t need to go down to the CINT level. Infact, everywhere around I see people like Philippe recommending the Execute method, with string arguments.

In the end, for those that stumble on this question after me, I copied what Wim did in the pyROOT source. He has done it already, so it actually isn’t hard. To get a working implementation took only about 6-8 hours of work. That was without the interpreter lock, and some other corner casses (supporting interpreted classes, etc.).

Like pyROOT, it is relatively slow. Use directly compiled wrappers where possible. :slight_smile:

-Gordon.

P.S. Axel - I can’t wait for Clang. This stuff will be simpler, right?? :wink: