Valgrind (was: TPad::Divide)

From: Christian Schmitt <>
Date: Wed, 05 Jan 2005 16:42:13 +0100

Hi Rene,

I have a question about valgrind: did you manage to get it running on lxplus ? I have installed it but it complains because it cannot allocate enough memory:

~/public/Valgrind/bin/valgrind --tool=addrcheck /bin/true valgrind: mmap(0x80cf000, -1477242880) failed during startup. valgrind: is there a hard virtual memory limit set? ===

I'm trying to debug a problem with program and root (it crashes only at CERN and not at my university so I need to debug it at CERN).



Rene Brun wrote:

> Hi Thomas,
> valgrind is a very nice system that can save you a lot of time discovering
> things like uninitialized variables, double deletes, showing a profile
> of the memory use, etc. For more info about valgrind, see:
> for example to run valgrind on your root.exe application, do:
>   valgrind --tool=addrcheck root.exe
> Rene Brun
> Thomas Bretz wrote:

>>Hi Rene,
>>I'm currently working with root 3.10/02. It is not easy to find a simple
>>script reproducing the problem. I can reproduce it, but not with a
>>simple program. Otherwise I may already know what the real reason is.
>>Sorry to ask, but what is 'valgrind'? If it is not too difficult I can try.
>>Rene Brun wrote:
>>>Hi Thomas,
>>>What you do should work unless there is very special case connected with signals
>>>that I do not see.
>>>Did you check (with a print in the destructor) that your object is deleted
>>>Could you run with valgrind?
>>>The best would be to send the shortest possible running script reproducing
>>>the problem. Please indicate your version of ROOT.
>>>Rene Brun
>>>Thomas Bretz wrote:
>>>>Dear all,
>>>>there is something I don't understand.
>>>>Assume I have created a TCanvas c. I have divided the canvas in two
>>>>subpads p1 and p2 and these are divided into p11, p12, p21 and p22 using
>>>>c.Divide(). Now I Draw an object in two different looks (eg
>>>>Draw("option1"), Draw("option2")) to p11 and p22.
>>>>Because I don't want to have the owenership of the object I call
>>>>SetBit(kCanDelete) for it.
>>>>If I now delete the canvas something - in my opinion - strange happens.
>>>>Because the two subpads are not in gROOT->GetListOfCleanups() it seems
>>>>that under some circumstances (which I cannot resolve) p11 _and_ p22 are
>>>>trying to delete my object and I get a crash. On the other hand the
>>>>Canvas containing the objects are in the ListOfCleanups and each of the
>>>>object - when deleted - should call recursiveRemove which should - in
>>>>all of its subpads - remove the object from all ListOfPrimitves.
>>>>Simply adding p1 and p2 to the ListOfCleanups solves the Problem. Does
>>>>somebody have any idea what may go on?
>>>>There is only one thing else which might be important: The object (in
>>>>its Draw function) calls
>>>>"MyClass", this, "EventInfo(Int_t,Int_t,Int_t,TObject*)");
>>>>I disconnect the Signal in the destructor.
>>>>Best regards,

> Received on Wed Jan 05 2005 - 16:42:25 MET

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