Re: [ROOT] Problem reading a TRef'd object

From: Rene Brun (
Date: Wed Jan 07 2004 - 23:24:34 MET

Hi John,

Before written ClassA, use a dummy TRef to reference it,

  ClassA* a = new ClassA();
  TRef dummy = a; // this will do the job

Rene Brun

On Wed, 7 Jan 
2004, John Pretz wrote:

> Hello everybody.
> I'm trying out TRef and I ran into the following problem:
> I have a class ClassA and a class ClassB.  ClassB has a TRef to ClassA.  I 
> want to write them both to disk.  I do it two possible ways.  One works.  
> The other doesn't.
> If I 
> 1.) Create ClassA
> 2.) Create ClassB
> 3.) Make ClassB::fTRef point to ClassA
> 4.) Write ClassA and ClassB to file
> alls well, and I can read them both back in just fine.
> If however, I do this:
> 1.) Create ClassA
> 2.) Write ClassA to file
> 3.) Create ClassB and make it's TRef point to ClassA
> 4.) Write ClassB to file
> I read in ClassA and ClassB only to find that ClassB's TRef points to 0.
> Is there a way to make this work for me?  I would really like to be able 
> to write ClassA to file before even creating the object that will point to 
> it.  I hunted around on this list's archives and couldn't find any 
> solutions.
> I included some code.  Just 'make' should compile all the code and run my 
> problem scripts.  (I'm using ROOT 3.10.02 on a RedHat 9 machine)
> Thanks in advance.
> John 

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