Segfault in app reading a custom class

Hi all,

I have a segfault when ending an application that is reading a file that contains a custom class (MUH1D - a new subclass of H1D). The (core parts) of the code worked a year or two ago, but now I am trying to get it working with a different environment and build set up and I think I am missing something in the dictionary generation or something similar.

The backtrace looks like this:

(lldb) bt

  • thread #1: tid = 0x46e97, 0x000000010096485d`TList::FindObject(TObject const*) const + 45, queue = ‘’, stop reason = EXC_BAD_ACCESS (code=EXC_I386_GPFLT)
    • frame #0: 0x000000010096485d libCore.soTList::FindObject(TObject const*) const + 45 frame #1: 0x000000010096434f libCore.soTList::Clear(char const*) + 143
      frame #2: 0x0000000100962c63 libCore.soTHashTable::Clear(char const*) + 83 frame #3: 0x00000001009622a9 libCore.soTHashList::Delete(char const*) + 57
      frame #4: 0x000000010098d16b libCore.soTClass::SetUnloaded() + 171 frame #5: 0x000000010095c66f libCore.soROOT::RemoveClass(char const*) + 95
      frame #6: 0x0000000100995924 libCore.soROOT::TGenericClassInfo::~TGenericClassInfo() + 148 frame #7: 0x00007fff8ced9521 libsystem_c.dylib__cxa_finalize + 200
      frame #8: 0x00007fff8cedb68b libsystem_c.dylib`exit + 15

This is with ROOT v5-34-18. The code looks like so (it was originally much longer, but has been chopped down):

int main() {
return tryToRead();
int tryToRead() {
TFile f(“wroteSomething.root”);
return 0;

The code that writes the files appears to work fine (the custom class histograms make nice plots, etc.). Chopped down it looks like so:

int main() {
MUH1D* a = new MUH1D(“a”,“going to disk”, 10, 0., 10. );
TFile f(“wroteSomething.root”,“recreate”);
a->Write(“MyHist”); //the name in the file is MyHist
return 0;

Of course, the class definition is long, but the most relevant file is probably the Linkdef.h, which looks like this:

#ifdef CINT
#pragma link off all globals;
#pragma link off all classes;
#pragma link off all functions;
#pragma link C++ nestedclasses;

#pragma link C++ namespace PlotUtils;

#pragma link C++ class PlotUtils::MULatErrorBand+;
#pragma link C++ class PlotUtils::MUVertErrorBand+;
#pragma link C++ class PlotUtils::MUH1D+;


Additionally, in the Makefile I produce a dictionary via (again, edited down a bit for brevity):

ROOTDICTHEADERS = MULatErrorBand.h MUVertErrorBand.h MUH1D.h MUApplication.h

mv $(TARGET) …/lib

$(OBJS): %.o: %.cxx %.h
$(CXX) $(CXXFLAGS) $(INCLUDE) $(ROOTINC) -c $< -o $@

rootcint -f $@ -c $(CXXFLAGS) -p $^

I’ve Googled around a bit using snippets from the backtrace but I don’t see anything promising. Any ideas?


it seems like that during the cleanup of TClass, the internal type-system of root, something goes wrong: it could be a double delete.
It would be helpful to have a standalone reproducer.



One thing that might help is to create a TApplication object in your main.