TMapFile

Piergiorgio Cerello (cerello@to.infn.it)
Fri, 28 Aug 1998 10:35:00 +0200 (MET DST)


Dear rooters,

I get a segmentation fault when trying to open a memory mapped file.

Here is the producer's code:

...

TH1F *lmdmult;

...

TMapFile *mmap = TMapFile::Create("lmd.map","RECREATE", 2000000,"Lmd
memory mapped file with histograms");
mmap->Print();

...

lmdmult = new TH1F("lmdmult","lmd multiplicity",200,-0.5,199.5);

...

(loop) {

...

lmdmult->Fill((Float_t) nhlmd);

...

mmap->Update();
mmap->ls();
}

The output is:

Memory mapped file: lmd.map
Title: Lmd memory mapped file with histograms
Option: CREATE
Mapped Memory region: 0x407a7000 - 0x4098f480 (1.91 MB)
Current breakval: 0x407af000

...

lmdmult TH1F 1320 (from mmap->ls();)

When I try to access the lmd.map file from a ROOT session, I give:

TMapFile *mfile = TMapFile::Create("lmd.map");

and I get back:

Segmentation fault
bash$

Something different happens if I give a small size to the .map file.
With 20000 istead of 2000000, I can access the file from the consumer,
but I get a segmentation fault when I try to update it from the producer.

Any suggestion?

Thanks,

Piergiorgio