Dealing with multiple dictionaries

ROOT
1

I have a problem compiling via Makefile two TObject-derived classes whose code shares the same class: I get

MySecondClass_Dict.o: In function `TheCommonClass::Class_Name()':
MySecondClass_Dict.C:(.text+0x0): multiple definition of `TheCommonClass::Class_Name()'
MyFirstClass_Dict.o:MyFirstClass_Dict.C:(.text+0x0): first defined here
// etc for other methods of TheCommonClass

which makes me think I am not dealing correctly with dictionaries.

My code structure is

[ul]
[li]NtupleReader, a TObject-derived class which loops over a TTree containing TClonesArrays;
[/li]
[li]MyFirstClass, daughter of NtupleReader (performs one analysis);
[/li]
[li]MySecondClass, daughter of NtupleReader (performs another analysis), sharing the TObject TheCommonClass with MyFirstClass [size=85](this object is not logically common to all >2 analyses, so I do not define it in the common parent)[/size];
[/li]
[li]theAnalysisRunner, a simple C++ main which calls one of the two analyses depending on user’s choice.[/li][/ul]

I have two LinkDef files for the daughter classes,

[code]// LinkDef_MyFirstClass.h ::: LinkDef_MySecondClass.h
#ifdef CINT

#pragma link off all globals;
#pragma link off all classes;
#pragma link off all functions;

#pragma link C++ nestedclass;

#pragma link C++ class TheCommonClass+;

#pragma link C++ class MyFirstClass+; // in the first file only
#pragma link C++ class MySecondClass+; // in the second file only

#endif // CINT
[/code]

one for the parent class

[code]// LinkDef_NtupleReader.h
#ifdef CINT

#pragma link off all globals;
#pragma link off all classes;
#pragma link off all functions;

#pragma link C++ nestedclass;

#pragma link C++ class Muon+; // this and many other TObject-derived classes stored in TClonesArrays (I omit them for the sake of clarity)

#pragma link C++ class NtupleReader+;

#endif // CINT
[/code]

and in the Makefile I do

[code]// Makefile
CC = g++
CFLAGS = -Wall -c
ROOTFLAG = ${ROOTSYS}/bin/root-config --cflags --libs

DICTEXEC = ${ROOTSYS}/bin/root-config --exec-prefix/bin/rootcint

theAnalysisRunner: theAnalysisRunner.o MyFirstClass.o MySecondClass.o NtupleReader.o TheCommonClass.o Muon.o NtupleReader_Dict.o MyFirstClass_Dict.o MySecondClass_Dict.o
$(CC) -Wall $^ $(ROOTFLAG) -o $@

NtupleReader_Dict.C: NtupleReader.h Muon.h LinkDef_NtupleReader.h
$(DICTEXEC) -f $@ -c -p $^

MyFirstClass_Dict.C: MyFirstClass.h NtupleReader.h TheCommonClass.h LinkDef_MyFirstClass.h
$(DICTEXEC) -f $@ -c -p $^

MyFirstClass_Dict.C: MySecondClass.h NtupleReader.h TheCommonClass.h LinkDef_MySecondClass.h
$(DICTEXEC) -f $@ -c -p $^

.SUFFIXES: .C .o

.C.o:
$(CC) $(CFLAGS) -o $@ $< root-config --cflags
[/code]

What am I doing wrong? Actually if I merge the two dictionaries for the derived classes everything is okay, but I would prefer to keep the development of the two analyses completely separated.

2

Hi,

You should only generate the dictionary for CommonClass once (literally the consequences of doing it twice are the duplicate symbols you are seeing). In your context, it seems you will need to create a 3rd dictionary just for the CommonClass.

Cheers,
Philippe.