The following simple macro causes a segmentation violation if I
uncomment
the mfile->Update line. This is ROOT 2.22/09, CINT 5.14.8.
-B
--
{
TH1S *monhisto = new TH1S("eventnr","event_nr",101,-0.5,100.5);
TH1S *monhisto2 = new TH1S("eventnr2","event_nr2",101,-0.5,100.5);
mfile = TMapFile::Create("onhistos.map","RECREATE",
10000000,"blabla");
mfile->Add(monhisto,"eventnr");
for (Int_t i = 0; i < 52; i++) { monhisto->Fill(i); }
monhisto2->Add(monhisto,monhisto2);
//mfile->Update(monhisto);
mfile->Close();
monhisto2->Draw();
}