Re: Strange TClonesArray problem

Hi Axel, thanks this debugging procedure pointed me to discover the problem, there was a missing namespace in fact it is MyNS::MyClass and not MyClass. I guess one cannot expect name lookup to work in this context, right? :-) I can use MyClass without MyNS everywhere inside this piece of code.
Now it seems to work (I would like to start filling the TClonesArray with the actual data to be sure but at least it does not crash) There is the issue of why getting a crash in the first place? Couldn't there be a away to stop gracefully? I guess a check for nullptr in a TClass::GetClass is missing somewhere in

  TClass::GetStreamerInfo(int)?

In fact one gets a message "Error in<TClonesArray::SetClass>: called with a null pointer" (lost in the output of one's application... I was just wondering whether this info could be used in the GetStreamerInfo.

Thanks,
filimon

On 01/19/2011 02:32 PM, Axel Naumann wrote:
> Hi,
>
> can you call
>
> gROOT->ProcessLine(".class MyClass")
> if (TClass::GetClass("MyClass")) TClass::GetClass("MyClass")->Dump()
> else printf("No TClass for MyClass!\n");
>
> before writing out the tree? What's the output?
>
> Cheers, Axel.
>
> Filimon Roukoutakis wrote on 01/19/2011 02:22 PM:
>> Hi, I get a strange problem related to TClonesArray. When initiliazing
>> on a MyEvent class ctor a member fMyArray with new
>> TClonesArray("TParticle", 100000), even TClonesArray("TClonesArray",
>> 10000000)!) everything works like a charm. But when doing new
>> TClonesArray("MyClass", 100000) I get the wonderful output below, when
>> eventually trying to write MyEvent in a TTree. MyClass inherits from
>> TObject, has ClassDef and an appropriate entry in my linkdef.h #pragma
>> link C++ class MyClass+; Is is more simple than a TParticle (5 Int_t, 10
>> Double_t, no mult inheritance, no allocation, no pointers, just a POD
>> 5*32+10*64+TObject). What could be the problem (ie is there any
>> additional requirement for MyClass)? The problem persists even if I use
>> the default second argument for TClonesArray (I believe it is 100). Thanks,
>> filimon
>>
>> *** Break *** segmentation violation
>> .......
>> .......
>>
>> ===========================================================
>> #10 0x00900e94 in TClass::GetStreamerInfo(int) const () from
>> /opt/root/v5-28-00/lib/libCore.so.5.28
>> #11 0x06e82b03 in TBufferFile::ForceWriteInfoClones(TClonesArray*) ()
>> from /opt/root/v5-28-00/lib/libRIO.so
>> #12 0x008dbabf in TClonesArray::Streamer(TBuffer&) () from
>> /opt/root/v5-28-00/lib/libCore.so.5.28
>> #13 0x008feb84 in TClass::StreamerTObjectInitialized(void*, TBuffer&,
>> TClass const*) const () from /opt/root/v5-28-00/lib/libCore.so.5.28
>> #14 0x06e880b7 in TBufferFile::WriteObjectClass(void const*, TClass
>> const*) () from /opt/root/v5-28-00/lib/libRIO.so
>> #15 0x06e84eba in TBufferFile::WriteObjectAny(void const*, TClass
>> const*) () from /opt/root/v5-28-00/lib/libRIO.so
>> #16 0x06e87727 in TBufferFile::WriteFastArray(void**, TClass const*,
>> int, bool, TMemberStreamer*) () from /opt/root/v5-28-00/lib/libRIO.so
>> #17 0x06f530a3 in int TStreamerInfo::WriteBufferAux<char**>(TBuffer&,
>> char** const&, int, int, int, int) () from /opt/root/v5-28-00/lib/libRIO.so
>> #18 0x0182b9ce in TBranchElement::FillLeaves(TBuffer&) () from
>> /opt/root/v5-28-00/lib/libTree.so
>> #19 0x01821720 in TBranch::Fill() () from /opt/root/v5-28-00/lib/libTree.so
>> #20 0x01827f10 in TBranchElement::Fill() () from
>> /opt/root/v5-28-00/lib/libTree.so
>> #21 0x01827ee8 in TBranchElement::Fill() () from
>> /opt/root/v5-28-00/lib/libTree.so
>> #22 0x01872aff in TTree::Fill() () from /opt/root/v5-28-00/lib/libTree.so
>>