How to make a tree with size larger than 2G?

I try to use TTree::SetMaxTreeSize(ULong64_t maxsize); however, it seems that the maxsize is not a 8 bytes word, but a 4 bytes signed long since it can’t take any number larger than 2147483647. Then how can I make the tree size larger than 2G bytes?

Thank you!

I suspect something wrong on your side when setting the Long64_t value.
Do something like

Long64_t mymax = 7000000000ll; //note the "ll" at the end TTree::SetMatTreeSize(mymax);