Hi 0ndrej (with a "zero", interesting),
> > TClonesArray *fParticles; // Array with particles
> > TIter *fpart_iter; //! caching the current ptr to
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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