[ROOT] Using TMapFile with a batch producer

From: Alberto Baldisseri (a.baldisseri@cea.fr)
Date: Wed May 10 2000 - 12:18:31 MEST 

Hi rooters,
    I am trying to use the TMapFile class to do a monitoring. I have a
producer task (batch)
that read the events from the DAQ and store some histograms in a
TMapFile. I would like
to access those histograms with an interactive root session. When I try
to open the TMapFile
from the root session I get a segmentation fault :

TMapFile* mfile = TMapFile::Create("hsimple.map")
 *** Break *** segmentation violation


    I code a simple producer as hprod.C but running in batch as follows
:

//
// Batch producer
//
#include <TROOT.h>
#include <TH1.h>
#include <TH2.h>
#include <TProfile.h>
#include <TMapFile.h>
#include <TRandom.h>

int  main(int argc, char *argv[])

{
  TROOT myroot("myroot","ALICE DAQ events");
  TMapFile* mfile = TMapFile::Create("hsimple.map","RECREATE", 100000,
         "Demo memory mapped file with histograms");

  TH1F* hpx    = new TH1F("hpx","This is the px distribution",100,-4,4);

  TH2F* hpxpy  = new TH2F("hpxpy","py vs px",40,-4,4,40,-4,4);
  TProfile* hprof  = new TProfile("hprof","Profile of pz versus
px",100,-4,4,0,20);

   // Set a fill color for the TH1F
  hpx->SetFillColor(48);

  // Print status of mapped file
  mfile->Print();

  // Endless loop filling histograms with random numbers
  Float_t px, py, pz;
  int ii = 0;
  while (1) {
    //    gRandom->Rannor(px,py);
    pz = px*px + py*py;
    hpx->Fill(px);
    hpxpy->Fill(px,py);
    hprof->Fill(px,pz);
    if (!(ii % 10)) {
      mfile->Update();       // updates all objects in shared memory
      if (!ii) mfile->ls();  // print contents of mapped file after
    }                         // first update
    ii++;
  }
}

    The interactive examples in the tutorials (hprod.C and hcons.C)
works fine, so
what is the difference with the batch ? Perhaps I miss someting ? I try
this with
root versions 2.23.09 and 2.24.04 on Linux RH6.2. This example have
worked last
year with root version 2.22.

Anybody have an idea ?

Regards,

Alberto

--
+-------------------------------+------------------------------------+
| Alberto BALDISSERI            | Tel : (33-1) 69 08 93 33           |
| DAPNIA/SPhN, Bat 703 pièce 42 | Fax : (33-1) 69 08 75 84           |
| CEA Saclay                    | E-mail : a.baldisseri@cea.fr       |
| F 91191 Gif-sur-Yvette cedex  |                                    |
+-------------------------------+------------------------------------+

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