Hi Peter,
I corrected in the ROOT svn trunk an existing problem with handling data
member
of literal type (no typedef) unsigned long long.
Now the problem that you are seeing is linked to the fact that stdint.h
contains:
#if __WORDSIZE == 64
typedef unsigned long int uint64_t;
#else
__extension__
typedef unsigned long long int uint64_t;
#endif
so that for ROOT uint64_t is a 'long' on 64 bit machines and a 'long long'
on 32 bit machine. Since we do not give uint64_t any special treament
(we use U/Long64_t for this purpose), the representation of you class
are different on both machine.
However this is usually not a problem (long are stored as 8 bytes
quantities on all platforms).
There 2 possibilities. Either you are seeing the message:
Warning in <TStreamerInfo::BuildCheck>:
The StreamerInfo of class myclass read from file ull.root
has the same version (=1) as the active class but a different checksum.
You should update the version to ClassDef(myclass,2).
Do not try to write objects with the current class definition,
the files will not be readable.
In which case I would recommend:
a) change all uint64_t into ULong64_t
b) increase the class version in your header files.
and your code will work without problem and be able to read older files.
If you are not receiving this message then I am guessing that you
are __updating__ on a 32 bits machine a TTree object
that was created on 64 bits machines.
If this is the case, you must instead create a new TTree and use the
old and new tree (for reading) using a TChain.
Cheers,
Philippe
________________________________
From: Philippe Canal [mailto:
pcanal@...]
Sent: Monday, October 08, 2007 5:00 PM
To: 'Peter Cogan'; '
cint@...'
Cc: '
veritas-oawg@...'
Subject: RE: [CINT] 32 / 64 bit compatibility and the unsigned long long
Hi Peter,
I can not reproduce this problem. I just tried to write a small class
containt uint64_t and
write it on a 32 bit machine and then try to read it on a 64 bit machine and
then in the
same session to try to write again without any problem. [This is with the
trunk of the
svn repository]
Which version of ROOT are you using?
Could you provide a complete running example reproducing the problem?
Thanks,
Philippe.
________________________________
From:
owner-cint@... [mailto:
owner-cint@...] On Behalf Of
Peter Cogan
Sent: Thursday, September 27, 2007 3:33 PM
To:
cint@...
Cc:
veritas-oawg@...
Subject: [CINT] 32 / 64 bit compatibility and the unsigned long long
Dear CINT coders,
one of the cint limitations listed here:
http://root.cern.ch/root/Cint.phtml?limitationsis that it does not distinguish between unsigned long long and signed long
long. We have found that this causes problems reading a ROOT file written on
a 32 bit machine into a 64 bit machine and vice versa. Specifically, we get
errors such as:
Error in <TStreamerInfo::WriteBuffer>: The element VATime::fDayNS type 217
(unsigned long long) is not supported yet
where VATime::fDayNS is a uint64_t
Unfortunately, we have started using 64 bit machines long after our analysis
development started, and it would be a major problem to remove all usage of
uint64_t from our analysis package, and would mean that we would loose
compatibility with old files.
Interestingly, I note that here:
http://root.cern.ch/twiki/bin/view/ROOT/CINTyou say that many of the limitations will be removed in a new version in
2007. The version currently available is 5.16.16, November 24, 2006
So, it would be nice to know if the unsigned long long will be handled fully
in the new version, and when you might expect it to become available.
kind regards
Peter Cogan
--
Peter Cogan
skype name: petercogan
skypein number: +1 520 413 1472
Steward Observatory
933 N. Cherry Avenue
Tucson
Arizona 85719
Phone: +1 520 670-5749
Fax: +1 520 670-5714
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