Re: TMapFile opened in update mode ...

Piergiorgio Cerello (cerello@to.infn.it)
Mon, 2 Nov 1998 12:13:18 +0100 (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
>