Linking in mac os x (10.8)

Question

I'm trying to compile a multi file bit of code which up until now has been working fine. But now I am getting some linker errors. I have a class definition 'njPhaseSpace' which is reported as being:

     ld: duplicate symbol njPhaseSpace::njPhaseSpace(int)in Source/Currents.o and
     /var/folders/p8/0bwv51kn2w5cx4jnsg6xm7340000gn/T//ccb0Psoz.o for architecture x86_64 

I have no idea what the /var/folder/.../ccb0Psoz.o file is about and it isnt (intentionally) begin used in my project. if I change the name to something different - but similar - such as njPhaseSpaceX it will compile and link up fine. But then I clean the project using 'make clean' and when I try to remake I get the same link error again! (but with a different /var/.../XXXXXX.o file) Any suggestions? Cheers

UPDATE: More strange things: When I look in the /var/folder/... directory to see which file is causing the duplication no such file exists!

UPDATE: The njPhaseSpace source file is:

// Standard header files
#include <iostream>
#include <string.h>
#include <stdlib.h>
#include <vector>
#include <stdio.h>
#include <math.h>
#include <complex>
#include <iomanip>
#include "LoadBar.h"

// CLHEP header files
#include <CLHEP/Vector/LorentzVector.h>
#include <CLHEP/Random/RanluxEngine.h>

// More convenient label for four-vectors
typedef CLHEP::HepLorentzVector HLV;

// Definition of structure to hold the phase-space point
struct ParticleStruct {
HLV pa;
HLV pb;
HLV pep;
HLV pem;
HLV p1;
HLV p2;
HLV p3;
double xa;
double xb;
} ;

// A class for the n-jet phase space
class njPhaseSpace {

private:
// Incoming Particle Momenta
HLV pa;
HLV pb;

// Emitted leptons
HLV pep;
HLV pem;

// Outgoing parton momenta
std::vector <HLV> OutgoingPartons;

// Kinematic factors
double xa;
double xb;

public:
// Constructor for class
njPhaseSpace(int n);

// Returns a vector of the outgoing parton momenta
std::vector <HLV> ReturnOutgoingPartons() {
    return OutgoingPartons;
}

// HLV IncomingForward



} ;

// Class constructor - adds n vectors to the Outgoing array
njPhaseSpace::njPhaseSpace(int n) {
// Add n final states to the OutgoingPartons vector
for (int i = 0; i < n; i++) {
    HLV temp;
    OutgoingPartons.push_back(temp);
}
}

UPDATE: This problem goes away when the class constructor is included in the body of the class definition. Whilst its good I can avoid this it doesnt really help because now to develop my class everything will have to sit inside the definition.

UPDATE: The makefile used to compile (Analysis is something seperate I am currently running make Explorer -j8):

#/bin/bash

# CXX Compiler
CXX = g++

# Directories For Compilation
INCDIR = MadGraph
LIBDIR = MadGraph
SRCDIR = Source

# Compilation Flags
CXXFLAGS = -O3 -lm
LIBFLAGS = $(shell clhep-config --libs) $(shell fastjet-config --libs) $(shell clhep-config --libs) $(shell root-config --libs)
INCFLAGS = $(shell clhep-config --include) -I/$(INCDIR) -I$(SRCDIR) -I. $(shell fastjet-config --cxxflags --plugins) $(shell clhep-config --libs) $(shell root-config --cflags)
FLAGS = $(CXXFLAGS) $(LIBFLAGS) $(INCFLAGS)

# Object Files
Objects    = $(addprefix $(SRCDIR)/, Currents.o mstwpdf.o LoadBar.o)
MadObjects = $(addprefix $(LIBDIR)/, HelAmps_sm.o Parameters_sm.o read_slha.o  CPPProcess2j.o CPPProcess3j.o)

# Main targets
all: Analysis Explorer

Analysis: $(SRCDIR)/Analysis2jepem.cxx $(Objects) $(SRCDIR)/CGenerator2jepem.o
$(CXX) $(SRCDIR)/Analysis2jepem.cxx -o $@ $(FLAGS) $(Objects) $(SRCDIR)/CGenerator2jepem.o

Explorer: $(SRCDIR)/qQepemqQ_Explorer.cxx $(Objects) $(MadObjects) $(LIBDIR)/libmodel_sm.a 
$(CXX) $(SRCDIR)/qQepemqQ_Explorer.cxx -o $@ $(FLAGS) $(Objects) -lmodel_sm -L$(LIBDIR)

# Build object files
$(Objects):
$(CXX) -c $(@:.o=.cxx) -o $@

# Build the MG5 object code
$(MadObjects):
$(CXX) -c $(@:.o=.cxx) -o $@ -I../

$(SRCDIR)/CGenerator2jepem.o:
$(CXX) -c $(@:.o=.cxx) -o $@

# Build the Standard Model library
$(LIBDIR)/libmodel_sm.a: $(MadObjects)
$(AR) cru $@ $^
ranlib $@

# Debugging flags
debug: CXX += -g -Wall -pendantic
debug: all

# Create a clean build
.PHONY: clean
clean:
rm -f $(Objects) $(MadObjects) $(LIBDIR)/2j/libmodel_sm.a $(LIBDIR)/3j/libmodel_sm.a $(TARGET) $(SRCDIR)/CGenerator2jepem.o Analysis Explorer

Answer 1

The problem is that the class constructor is defined in the header file as:

    njPhaseSpace::njPhaseSpace(int n) {
// Add n final states to the OutgoingPartons vector
for (int i = 0; i < n; i++) {
    HLV temp;
    OutgoingPartons.push_back(temp);
}

Either put it in the class declaration, or into it's own separate .cpp file that is compiled and linked separately.

This is no different from creating a non-inline/non-static/non anonymous namespaced function in a .h file and #including it in multiple .cpp files.

Answer 2

This error is sometimes prompted if you include the files like this: File a included in file b; Filb and file a included in file c. Can you try to put the "static" keyword in front of the class constructor that gives you problems?