Hello Rene,
Thank you for the reply. I re-read the documentation you reccommended, and
still don't understand through what method the classes are serialized when
split_level=1. From my tests I think it is not the Streamer method.
The documentation states:
"In split mode, a data member cannot be a pointer to an array of basic
types."
"In split mode, a data member cannot be a C structure."
So an array of structures is definetely out of the question with the
standard code. But can I write my own?
If I can not, is there a way to make writing a tree of my objects more
efficient than the "create" "write" "delete" cycle that is currently used?
The full code for my classes (the one with the pointer into a big memory
array) can be found at:
http://improv.unh.edu/root_problem.txt. This file is a concat of 4 files:
TBOSBankHeader.h and .cc and TBOSRoot.h and .cc.
Your help is much appreciated,
Maurik Holtrop
P.S. Here is some example code.
Instead of the full class, I send you an example wich illustrates that the
Streamer function of a class does not get called when writing the clas with
split_level=1. This example however, works perfectly fine. When split level
=1 the variables are written to disk through some other mechanism. However,
for classes (unlike this example) that *need* a highly customized streamer,
this means writing won't work.
The following macro (write.C) will print 10 times "Streamer called" when
split level is 0, but not when split level is 1.
/////////////////////////// write.C:
{
tempa *part=new tempa(1,2.);
TFile hfile("split.root","RECREATE","Demo ROOT file");
TTree *tree = new TTree("T","An example");
tree->Branch("tempa","tempa",&part,10240,0);
for(int i=0; i<10; i++){
part.i=i;
part.x=i*i*10.;
tree->Fill();
}
tree->Print();
hfile.Write();
hfile.Close();
}
////////////////////// test2.cc
#include "test2.h"
ClassImp(tempa)
ostream &operator<<(ostream &os,tempa &b)
{
os << " Int: " << b.i;
os << " Float: " << b.x;
os << " C: " << b.str << endl;
return(os);
}
void tempa::Streamer(TBuffer &R__b)
{
// Stream an object of class tempa.
cerr << "Streamer called\n";
if (R__b.IsReading()) {
Version_t R__v = R__b.ReadVersion(); if (R__v) { }
TObject::Streamer(R__b);
R__b >> i;
R__b >> x;
R__b.ReadStaticArray(str);
} else {
R__b.WriteVersion(tempa::IsA());
TObject::Streamer(R__b);
R__b << i;
R__b << x;
R__b.WriteArray(str, 256);
}
}
///////////////////// test2.h
#ifndef __CINT__
#include "TObject.h"
#endif
#include <iostream.h>
class tempa : public TObject{
public:
int i;
float x;
char str[256];
public:
tempa(){ cout << "******** tempa constructor called\n";};
~tempa(){cout << "######## tempa destructor called\n";};
tempa(int a,float b){
i=a;
x=b;
strcpy(str,"Initialized with constructor.");
}
void Print(){
cout << (*this) << endl;
}
friend ostream &operator<<(ostream &os,tempa &b);
ClassDef(tempa,1)
};
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