TTree::SetMaxTreeSize() and Long64_t

ROOT
1

Hi,
I don’t know if I am here right for this very basic question. Please don’t mind that I post it here. I am very grateful for every answer.
I am trying to compile a standalone program using root file with a large TTree object inside. So I have to set the max size of the tree using SetMaxTreeSize(). On Linux system that is not a great deal. But now I am trying to compile the same code for windows. And it turns in deed to be a problem: the following code won’t get compiled:

Long64_t size = 16000000000; TTree::SetMaxTreeSize(size);
The error message reads

To compile the program I chose to use Mingw as compiler.
The compiler seems to make no difference between Long_t and Long64_t. It doesn’t make sense if I can’t set the tree size bigger than 1900000000, which is the default value of the function. So there must be a solution and I must have made some mistakes. Please help me!

sincerely,

Simon Lu

2

Hi Simon,

Sorry, but Mingw compiler is not supported by ROOT. You can use the free Microsoft Visual Studio Express edition instead.

Cheers, Bertrand.

3

you are missing a LL behind your number declaration so the compiler knows the integer literal is of long long type (=64bit integer of gcc) and not long:
Long64_t size = 16000000000LL;
(LLU for unsigned long long)