Using TTree Branch for a class that virtually inherits

ROOT
1

Hi all.

I’d really like to use multiple virtual inheritance in my data structure classes. I have been trying to do the following:

class Base {
…
}

class Event : public virtual Base {
…
}

fillTree{
TTree *t = new Tree(…);
Event *e = new Event();
t->Branch(“eventBranch”, “Event”, &e, 32000, 99);

//loop and fill some Event members

t->Write();
}

My code compiles, but always breaks at the TTree::Branch. If I do not virtually inherit class Base, then it completely works fine.

Can anybody tell me what I’m doing wrong? Or is this a ROOT limitation?

The output from gdb that I get at this line is:

Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000028
0x00000001000036c9 in G__EventDict_146_0_26 ()

Thanks for your help.

Adam

ps - yes, I know that there is not any multiple inheritance at this point, but there would be if I could first get this to work.

2

Hi,

Virtual inheritance is currently not supported in ROOT I/O.

Cheers,
Philippe.

3

Salut Philippe,

[quote=“pcanal”]
Virtual inheritance is currently not supported in ROOT I/O.[/quote]

Are there any (concrete) plans to support this in the future? (If so, when?)

Thanks!

Charles

4

Hi Charles,

We are not planning on adding this support in the near term ; it requires some significant refactoring of the ‘meta’ package and we are not planning to do such refactoring until after we have significantly upgraded the dictionary generator and interpreter.

Cheers,
Philippe.

5

Hi Philippe,

Thanks for the quick reply. :smiley: Am I correct that the significant upgrade to the dictionary generator and interpreter is a timescale of a couple years (give or take)?

Thanks!

Charles

6

Yes :slight_smile:

Cheers,
Philippe.