friend functions are not class member functions. They are normal
functions that may directly access class variables. Therefore you
need to add a pragma statement for each friend function, like for
other functions. For example this is what I use to export some
TString operator friend functions:
#pragma link C++ function Strip;
#pragma link C++ function StrDup;
#pragma link C++ function operator+(const TString&,const TString&);
#pragma link C++ function operator+(const TString&,const char*);
#pragma link C++ function operator+(const char*,const TString&);
Cheers, Fons.
>
>
>
> Hi,
>
> there seems to be a problem with rootcint (CINT ?) processing of the
> friend functions illustrated be the example below. Or may be somebody could
> comment on what's wrong with this example ?
>
> Thanks, Pasha.
>
> ------------------------------------- v22.hh
> #include "TObject.h"
>
> class V2 {
> public:
> // ****** data members
> double X,Y;
> // ****** constructors
> V2 ();
> V2 (double x0, double y0);
>
> double x() { return X; }
> double y() { return Y; }
>
> friend V2 operator + (V2& v1, V2& v2);
>
> void set(double x, double y) { X=x; Y=y; }
>
> V2 operator += (V2& v) { X+=v.X; Y+=v.Y; }
>
> V2 add (V2& v) { return V2(X+v.X, Y+v.Y); }
>
> friend V2 add (V2& v1, V2& v2) ;
>
> ClassDef(V2,1)
>
> };
>
> -------------------------------------- v22.cc
> #include "v22.hh"
>
> ClassImp(V2)
>
> V2::V2() { X = 0.; Y = 0.; }
>
> V2::V2(double x0, double y0) { X = x0; Y = y0; }
>
> V2 operator + (V2& v1, V2& v2) {
> return V2(v1.X+v2.X,v1.Y+v2.Y);
> }
>
> V2 add (V2& v1, V2& v2) {
> return V2(v1.X+v2.X, v1.Y+v2.Y);
> }
>
> ---------------------------------------- LinkDef.h
> #ifdef __CINT__
>
> #pragma link off all globals;
> #pragma link off all classes;
> #pragma link off all functions;
>
> #pragma link C++ class V2;
>
> #endif
> ----------------------------------------------------
>
> Here is what I get (I compile a shared library and load it dynamically):
>
> /cdf/upgrade/tracking/murat/g3/test/glob>rootcint -f v22_cint.cc -c v22.hh LinkDef.h
> Note: operator new() masked c
> class V2 in v22.hh line 3 original base of virtual func
> /cdf/upgrade/tracking/murat/g3/test/glob>gcc -shared -o v22.so -I../include -I$ROOTSYS/include v22.cc v22_cint.cc
> /cdf/upgrade/tracking/murat/g3/test/glob>root
> No default font loaded
> *******************************************
> * *
> * W E L C O M E to R O O T *
> * *
> * Version 1.03/01 22 August 1997 *
> * Development version *
> * *
> * You are welcome to visit our Web site *
> * http://root.cern.ch *
> * *
> *******************************************
>
> CINT/ROOT C/C++ Interpreter version 5.13.21, Aug 12 1997
> Type ? for help. Commands must be C++ statements.
> Enclose multiple statements between { }.
> root [0] gSystem->Load("v22.so")
> (int)0
> root [1] V2 a(1.,1.);
> root [2] V2 b(2.,2.);
> root [3] V2 c;
> root [4] .p a
> (class V2)272285080
> 0x0 double X=1
> 0x8 double Y=1
> 0x0 private: static class TClass* fgIsA
> 0x0 private: long G__virtualinfo
> root [5] .p c
> (class V2)272285176
> 0x0 double X=0
> 0x8 double Y=0
> 0x0 private: static class TClass* fgIsA
> 0x0 private: long G__virtualinfo
> root [6] .p b
> (class V2)272285128
> 0x0 double X=2
> 0x8 double Y=2
> 0x0 private: static class TClass* fgIsA
> 0x0 private: long G__virtualinfo
> root [7] c+=b;
> root [8] .p c; <-------------------------------**** up to now everything is OK
> (class V2)272285176
> 0x0 double X=2
> 0x8 double Y=2
> 0x0 private: static class TClass* fgIsA
> 0x0 private: long G__virtualinfo
> root [9] c = c+b; <-------------------------------***** call to friend function
> root [10] .p c the result is wrong
> (class V2)272285176 should be (4.,4.)
> 0x0 double X=2
> 0x8 double Y=2
> 0x0 private: static class TClass* fgIsA
> 0x0 private: long G__virtualinfo
> root [11] c = a.add(b);
> root [12] .p c
> (class V2)272285176
> 0x0 double X=3
> 0x8 double Y=3
> 0x0 private: static class TClass* fgIsA
> 0x0 private: long G__virtualinfo
> root [13] c = add(c,b); <--------------------------**** call to friend function
> Error: No symbol add(c,b) in current scope FILE:/var/tmp/haaa006XZ LINE:1
> *** Interpreter error recovered ***
> --------------------------------------------------------------------------------
>
>
-- Org: CERN, European Laboratory for Particle Physics. Mail: 1211 Geneve 23, Switzerland Phone: +41 22 7679248 E-Mail: Fons.Rademakers@cern.ch Fax: +41 22 7677910