[ROOT] Shared file

From: Yuriy Prokazov (yuriypro@narod.ru)
Date: Wed Feb 13 2002 - 13:50:14 MET


Dear ROOTers,
I'd like to make work 2 independent processes where one of them
writes information into the file and other reads it. If it is 
possible I would like to use TNetFile (if these processes are 
running on a different computers) or via TFile if (they are in 
the single box). I faced with following problem: from the WRITE
process I create file using TFile and create TTree object with
the single branch of a simple type. Every second WRITE process 
fills the branch and saves some amount of data. In the READ 
part I open the file using TFile::Open().

The problem is that in the READ call tree->GetEntries() always 
returns the same number. From the ROOT source code it is 
obviosly clear that it could return only the one value that have
been saved during initialization. 

But the same time file->GetFileSize() show that the file is 
growing.

Is there any way how to make independed reading/writing and say 
to READ process that the file was changed and it is required to
read new data?

Thank you.
Best regards,
Yuriy.



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