Re: [ROOT] Shared memories & TMapFile

From: Stefano Magni (stefano.magni@mi.infn.it)
Date: Wed Apr 24 2002 - 19:35:28 MEST


Dear Rene,
we have of course read carefully the documentation you suggest and
exactly followed the prescriptions. Nevertheless we still have problems:
when the consumer process remaps ( as read-only ) the TMapRegion created
by the producer, we notice that the single histo we store is shown to be
present in the Map File ( calling TMapFile Print() method ) but any call
to a method of the histo crash the program.

a snapshot from producer Print

Memory mapped file:   daq.map
Title:                DAQ Monitor Histograms
Option:               CREATE
Mapped Memory region: 0x67747000 - 0x6774f000 (0.03 MB)
Current breakval:     0x6774f000
   
a snapshot from consumer Print


Memory mapped file:   daq.map
Title:                DAQ Monitor Histograms
Option:               READ
Mapped Memory region: 0x67747000 - 0x677c1000 (0.48 MB)
Current breakval:     0x677c1000
Object               Class                Size      
cardDistribution     TH1F                 1024      

 *** Break *** segmentation violation


Thanks for any further suggestion.

	Stefano & Dario


> Hi Stefano & Dario,
> 
> Did you follow carefully the instructions given at:
> http://root.cern.ch/root/htmldoc/TMapFile.html#TMapFile:SetMapAddress
> 
> for SetMapAddress and MaptoAddress ?
> 
> Rene Brun
> 




-- 
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Dr. Stefano Magni
I.N.F.N Via Celoria 16, Milano
tel : 0250317738
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