Hi Ondrej,
We updated the ROOT code in CVS so that you original code would work
properly. I.e. it would __silently__ not save your TIter object. To
__know__ that the TIter object are not saveable you have to look up the
class definition/documentation and notice the statement:
ClassDef(TIter,0);
A few other classes in the ROOT code are not saveable. From now on you will
be able to have data member to those and the system will automatically mark
them as transient.
Cheers,
Philippe.
-----Original Message-----
From: owner-roottalk@pcroot.cern.ch
[mailto:owner-roottalk@pcroot.cern.ch]On Behalf Of 0ndrej Chvala
Sent: Thursday, October 16, 2003 8:17 AM
To: roottalk@pcroot.cern.ch
Subject: Re: [ROOT] cannot create object of class TIter
Hi Axel and other root masters :)
thanks for explanation, now I understant.
It might be a good idea to add this info (interrators cannot be saved
into TFile and here's how to deal with it) into Chapter14 of the
UserGuide. I found some notice about "//!" in the chaper about IO (page
174, UG ver 3.05), however even from that I would not decode that it
concerns iterrators and how....
thanks for the great root (the more I know it the more I appreciate the
developers...) and excellent support
cheers
0ndrej
>The important part is the "!" after the comment, which tells root not to
>save this member. The other puzzle: if you create a TFile beforehand, root
>will use that to cache / auto-save whatever tree you're dealing with - i.e.
>it will try to write that tree to file, and it will fail because one of
your
>classes has a TIter member.
>
>Adding //! will prevent root from taking this member into account when
>writing (you mark that member as non-persistent), and now you can place
your
>file creation wherever you want.
>
>Axel.
>
>
>
>
>>-----Original Message-----
>>From: owner-roottalk@pcroot.cern.ch
>>[mailto:owner-roottalk@pcroot.cern.ch]On Behalf Of 0ndrej Chvala
>>Sent: Wednesday, October 15, 2003 8:01 PM
>>To: Philippe Canal; roottalk@pcroot.cern.ch
>>Subject: Re: [ROOT] cannot create object of class TIter
>>
>>
>>Hi Philippe,
>>
>>Thanks for explanation, I just found that if I do not create the TFile
>>beforehand, it sudenly works, which puzzled me.
>>However I do not understand how should I modify the class to allow
>>saving the data into a TFile - your code looks same as the original.
>>Should I write my own streamer without the fpart_iter?
>>
>>thanks for help, best regards
>>0ndrej
>>
>>Philippe Canal wrote:
>>
>>
>>
>>>Hi Ondrej,
>>>
>>>A TIter object can not be saved onto a file (hence the system
>>>
>>>
>>you not even
>>
>>
>>>try to look it up).
>>>As a workaround (and a clarification of your code anyway, just
>>>
>>>
>>modify your
>>
>>
>>>class as follow:
>>>
>>> TClonesArray *fParticles; // Array with particles
>>> TIter *fpart_iter; //! caching the current ptr to
>>>iterator
>>>
>>>-----Original Message-----
>>>From: owner-roottalk@pcroot.cern.ch
>>>
>>>
>[mailto:owner-roottalk@pcroot.cern.ch]On
>
>
>>Behalf Of 0ndrej Chvala
>>Sent: Wednesday, October 15, 2003 7:05 AM
>>To: roottalk@pcroot.cern.ch
>>Subject: [ROOT] cannot create object of class TIter
>>
>>
>>Dear rooters,
>>
>>I have 2 classes, one describes an event and the other a track in that
>>event. The event contains a TClonesArray with the tracks and the
iterrator:
>>
>> TClonesArray *fParticles; // Array with particles
>> TIter *fpart_iter; // ptr to iterator
>>
>>When an new event is created, the TClonesArray is created:
>>
>> fParticles = new TClonesArray("TBigDSWriteParticle",1000);
>> fpart_iter = new TIter(fParticles);
>>
>>The classes can be compiled, loaded into root runtime, but when I try to
>>make a branch, it complaints:
>>root [0] .L /cern/root/lib/libEG.so
>>root [1] .L /cern/root/lib/libPhysics.so
>>root [2] .L ../lib/libmicro.so
>>root [3] TFile *tfile= new TFile("/tmp/dsttest.root","RECREATE");
>>root [4] TTree *tft = new TTree("tft","");
>>root [5] tfile->SetCompressionLevel(2);
>>root [6] TBigDSWriteEvent *myevent=new TBigDSWriteEvent();
>>root [7] TBigDSWriteParticle *mypart;
>>root [8]
>>tft->Branch("TBigDSWriteEvent","TBigDSWriteEvent",&myevent,5000000,1);
>>Error in <TClass::New>: cannot create object of class TIter
>>
>>The source codes are atached.
>>
>>Any help is greatly welcomed, I already tried to use other container
>>objects (TList, TObjArray), asked whom I can around but I'm still stucked.
>>
>>Thank you
>>0ndrej Chvala, NA49 << File: TBigDSWriteEvent.h >> << File:
>>TBigDSWriteParticle.h >> << File: TBigDSWriteEvent.cxx >> << File:
>>TBigDSWriteParticle.cxx >>
>>
>>
>>
>>
>>
>
>
>
>
>
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