Old ROOT open ROOT file created by new version of ROOT

ROOT
1

Dear Experts

When I open a TFile created by root v6.36.04, the open operation is done by root v6.24.02, I observed many error message like:


Error in <TList::Clear>: A list is accessing an object (0x2e8d580) already deleted (list name = TList)
Error in <TList::Clear>: A list is accessing an object (0x2e98770) already deleted (list name = TList)

How can I avoid this issue?

ROOT Version: 6.36.04 / 6.24.02
Platform: MacOS
Compiler: gcc

2

I guess @pcanal can help you.

3

You can either:

  • Download the tip of the v6-24-00-patches branch and build that version of ROOT

or

  • Disable the new behavior when writing the files, by to calling file->SetBit(TFile::k630forwardCompatibility);. Alternatively The rootrc key TFile.v630forwardCompatibility can be used to change the default to have the bit set for all TFiles
4

Thank you for you answer

>Download the tip of the v6-24-00-patches branch and build that version of ROOT
What do you mean tip? Sorry I’m a newbie.