really crazy crash

From: Tom Roberts <tjrob_at_fnal.gov>
Date: Tue, 22 Apr 2008 16:19:45 -0500

I am trying to debug a >2000 line Root macro by isolating the problem into a small macro (it works on 5.12-16 but crashes on 5.18). I keep getting frustrated by seemingly trivial crashes that do not seem to be the real problem. Here is another one that crashes on 5.16 and 5.18 (Linux, Fedora Core 8).

I thought CINT permitted one to omit the #includes in a macro file. This seems to not be the case, except for the remarkable fact that it works, but crashes on ".q".

Specifically: if I do:

.L test5.C
.q

root crashes.

If I do:

.X test5.C
.q

it prints "Ntuple 'VirtualDetector/Det1' opened" (i.e. the macro worked correctly) and then crashes on the .q.

Indeed, all that is needed is a declaration "TNtuple *ntuple" in the class to make this crash on .q.

If I uncomment the #include, all is well. Note that no #include of TFile.h seems to be needed, and attempts to display this problem with TFile all failed.

What is the difference between TFile and TNtuple? Do I really need to #include the class header for every Root class I use in a macro?
How does the macro execute correctly but crash on .q?

(my big macro does crash on .q, but it normally calls gApplication->Terminate(0) which does not crash, so this is not a problem to my users.)

Tom Roberts

// test5.C

//#include <TNtuple.h>

class PlotNtuple {

	TFile *file;
	TNtuple *ntuple;
public:
	PlotNtuple(const char *filename, const char *ntuplename);
	void scan();

};

PlotNtuple::PlotNtuple(const char *filename, const char *ntuplename) {

	file = 0;
	ntuple = 0;

	file = new TFile(filename,"READ");
	if(file->IsZombie()) {
		printf("Cannot read '%s'\n",filename);
		file = 0;
		return;
	}
	ntuple = dynamic_cast<TNtuple*>(file->Get(ntuplename));
	if(!ntuple) {
		printf("Cannot find NTuple '%s'\n",ntuplename);
		return;
	}
	printf("Ntuple '%s' opened\n",ntuplename);

}

void PlotNtuple::scan()
{
}

void test5()
{

	PlotNtuple *pn=new PlotNtuple("g4beamline.root","VirtualDetector/Det1");
	pn->scan();

}

Received on Tue Apr 22 2008 - 23:20:17 CEST