Re: TMapFile opened in update mode ...

From: Piergiorgio Cerello (cerello@to.infn.it)
Date: Mon Nov 02 1998 - 12:13:18 MET


Hello Valery,

  you can use 

  mfile->Update();

It should work.

I would also like to add a question to all rooters concerning shared
memories.
I'm filling shared memories in a standalone producer, and I would like to
reset them from the consumer, when the operator requires it.
I tried to open the sahred memory  from the consumer in "update" mode, but
then I couldn't reset the objects (histograms) it contained. 
I wonder wether it is possible or not...

        Thanks,

            Piergiorgio
 

On Mon, 2 Nov 1998, Valeriy Onuchin wrote:

> Hello Rooters!
> I would like to update objects in TMapFile, 
> it seemed to me that  changing option from 
> "RECREATE" -> "UPDATE" should do the work.
> 
> hprod.c
> >>
> >>  mfile = TMapFile::Create("hsimple.map","UPDATE", 100000,
> >>                        "Demo memory mapped file with histograms");
> 
>  but running hprod.C  doesn't update histos in hsimple.map ???
> 
> Does that mean that the  only way  to do that is 
> 1. open existing map file in READ mode 
> 2. copy histos from file to memory
> 3. close file
> 4. recreate the same file
> 5. add histos from memory to map file   
> 
>  ???
>  With  best regards.              Valery
> 



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