BufferFile::CheckByteCount and Streamer

[mfg]

Hi

When I add a new data member to my class, like this:

	  Int_t    ntcoll ;
	  Double_t *tcoll  ; //[ntcoll] 

and I create a tree, I get the following error in root (after I open the tree and do a tree->Scan(tcoll[0])):

Error in <TBufferFile::CheckByteCount>: object of class TWaveform read too many bytes: 257 instead of 256
Warning in <TBufferFile::CheckByteCount>: TWaveform::Streamer() not in sync with data on file /home/mfg/TCT_DB/analysed/2017-12-20_12-29-00_avb_LGAD_W5_I3_1.txt.root, fix Streamer()

If I remove this member everything is fine. Any hint on what could happen here?

I am using 6.12/04 in a CentOS 7.4.1708

echo $LD_LIBRARY_PATH 
/home/mfg/apps/root/lib:/afs/cern.ch/sw/lcg/contrib/gcc/4.8/x86_64-slc6/lib64:/home/mfg/TRICS_old
echo $ROOT_INCLUDE_PATH 
/home/mfg/apps/root/include:/home/mfg/TRICS_old
echo $ROOTSYS 
/home/mfg/apps/root
[

Thank you

[pcanal]

Hi,

Does TWaveForm have a ClassDef? Does it have a dictionary? If so did you use rootcling or genreflex? Either way, can you share the line where you requested the dictionary for TWaveForm? Did you recompile the dictionary after chaging TWaveForm.h?

Cheers,
Philippe.

[mfglinux_gmail]

Hello Philippe

thank you so much for your kind help.

Anwers:
Does TWaveForm have a ClassDef?
Yes

class TWaveform : public TObject {
   public:
          Some data members
	  Int_t    ntcoll ;
	  Double_t *tcoll  ; //[ntcoll] 
  private:
    Some data members
  
ClassDef(TWaveform,3) ; //ROOT RTTI
};

**Does it have a dictionary? If so did you use rootcling or genreflex? **
Yes, I use rootcling and the compilation goes as the attached script SimpleCompile.sh

@pcanal

Either way, can you share the line where you requested the dictionary for TWaveForm?

Pardon, I do not understand the question. .
In the implementation file I use ClassImp(TWaveform) (directly after all the includes).
I have a LinkDef.h which reads:
#ifdef CLING
#pragma link C++ class TMeas+; //add byte count
#endif

I attach as well the created TWaveform dictionary

Finally, I have cleaned/recompiled after every change.

SimpleCompile_sh.txt (1.3 KB)
TWaveDict.C (8.0 KB)

Please, let me know if you need the code. I can strip it off or send it in zipped format. It is made of 3 small classes and a main.

[pcanal]

Does TWaveForm have a ClassDef?
Yes

When adding the new data member, did you increase the version number (this is required).

#pragma link C++ class TMeas+; //add byte count

Do you have the same for TWaveform?

Actually the dictionary say you do not or at least it is missing the trailing +.
Missing the trailing + means that there is no automatic schema evolution.

Try increasing the version number and adding the trailing+ to the #pragma link for TWaveForm.

Cheers,

[mfg]

Yes ! These 2 advices fixed it!

Big relief !!
Thank you very much !