Details on the use of rootcint are given at:
http://root.cern.ch/root/RootCintMan.html
To run your example below, I recommend the following procedure.
1- Make a file test.hh (standard class definition)
2- Make a file LinkDef.h
3- rootcint -f test_cint.cc -c -I$ROOTSYS/include test.hh LinkDef.h
where:
//----file test.hh
#include <TObject.h>
class VECTOR {
protected:
int Size;
double* V;
public:
VECTOR();
ClassDef(VECTOR,1)
};
//----end of file.hh
//----file LinkDef.h
#ifdef __CINT__
#pragma link off all globals;
#pragma link off all classes;
#pragma link off all functions;
#pragma link C++ class VECTOR;
#endif
//----end of LinkDef.h
When running the rootcint command, you will get the following output:
Note: operator new() masked c
Note: operator delete() masked c
class VECTOR in test.hh line 2 original base of virtual func
*** Datamember VECTOR::V: pointer to fundamental type (need manual intervention)
The warning message about "fundamental type" means that rootcint was not able
to completly generate the code for VECTOR::Streamer. Here is the code generated:
//______________________________________________________________________________
void VECTOR::Streamer(TBuffer &R__b)
{
// Stream an object of class VECTOR.
if (R__b.IsReading()) {
Version_t R__v = R__b.ReadVersion();
R__b >> Size;
//R__b.ReadArray(V);
} else {
R__b.WriteVersion(VECTOR::IsA());
R__b << Size;
//R__b.WriteArray(V, __COUNTER__);
}
}
Because V is a pointer to a double, Root has no way to know the length
of what is pointed by V. In your case, it makes a good guess. You should
replace the two commented statements above:
//R__b.ReadArray(V);
//R__b.WriteArray(V, __COUNTER__);
respectively by:
R__b.ReadFastArray(V, Size);
R__b.WriteFastArray(V, Size);
(see TBuffer.h) for a list of useful service functions that can be called.
Note also that the class VECTOR defined above is already in Root (see class TArrayD).
Rene Brun
Pasha Murat wrote:
> I've been trying to figure out how to use linear algebra classes with ROOT.
> There are 2 basically different types of linear algebra packages on the market:
>
> - the ones using templated classes for vectors and matrices
> - the ones not using templates
>
> In one of the previous postings I asked about how to use templated classes
> with 'rootcint'. - May be it is just not possible?
>
> Using non-templated classes reveals other problems, an example is enclosed
> below.
>
> I'd appreciate any comments,
> thanks, Pasha.
>
> ----------------------------------------------- test.hh
> #include "root/Rtypes.h"
> class VECTOR {
> protected:
> int Size;
> double* V;
> public:
> VECTOR();
> ClassDef(VECTOR,1)
> };
>
> #ifdef __CINT__
> #pragma link off all globals;
> #pragma link off all classes;
> #pragma link off all functions;
> #pragma link C++ class VECTOR;
> #endif
> ------------------------------------------------
> /cdf/upgrade/tracking/murat/g3/test/glob>rootcint -f test_cint.cc -c -I../include -I$ROOTSYS/include test.hh
> Note: operator new() masked c
> Warning: Link requested for undefined class test FILE: LINE:0
> --------------------------------------------------------------------------------
>
> It looks like the file name matters here (does it really ? ) - if
> I rename test.hh into VECTOR.hh the diagnostics is quite different:
>
> --------------------------------------------------------------------------------
> /cdf/upgrade/tracking/murat/g3/test/glob>mv test.hh VECTOR.hh
> /cdf/upgrade/tracking/murat/g3/test/glob>rootcint -f test_cint.cc -c -I../include -I$ROOTSYS/include VECTOR.hh
> Note: operator new() masked c
> class VECTOR in VECTOR.hh line 2 original base of virtual func
> *** Datamember VECTOR::V: pointer to fundamental type (need manual intervention)
>
> --------------------------------------------------------------------------------
>
> - The 1st question here is what's wrong with having pointer to double ?
> - It is also interesting to know what kind of "manual intervention"
> user is supposed to provide
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