[ROOT] no memory mapped file capability available in 3.00

From: Robert Michaels (rom@jlab.org)
Date: Mon Oct 29 2001 - 20:50:22 MET


Using root 3.01-06 on Redhat 6.2 Linux with kernel 2.2.19-6.2.7, 
but my problem is observed on SunOS also, and disappears with a
sufficiently early version of root (e.g. 2.23-12).

I am having trouble using TMapFile.  I used the example
producer from http://root.cern.ch/root/html/examples/hprod.C.html
and in the second line it fails:

{
   gROOT->Reset();
   mfile = TMapFile::Create("hsimple.map","RECREATE", 100000,
                            "Demo memory mapped file with histograms");
// Script dies here.
}

The error message:
Error in <TMapFile::TMapFile>: no memory mapped file capability available
Error in <TMapFile::TMapFile>: mapped file not in mmalloc format or
already open in RW mode by another process

(To anticipate:  I did remove the file "hsimple.map" first.)

Interestingly, if I use root 2.23-12 or 2.21-08 the tutorial producer
works great, and the tutorial consumer sees the data, etc.  So, my 
question is what might be wrong with my use under 3.01-06 ? (problem 
also on 3.00-06). It seems unlikely to be a corrupted installation 
since I tried both my installed version and our computer center's 
version.  Same failure is seen on a SunOS installation.

thanks,
------------------------------------------------------
Robert W. Michaels      
www.jlab.org/~rom
phone (757) 269 7410   pager (757) 881 7897
Thomas Jefferson National Accelerator Facility
12000 Jefferson Ave, Newport News, VA 23606 USA



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