I'm trying to overload the "<<" operator for a template class. I've the definition of the class in a .h file and its implementation in a .cpp file.
/tmp/ccjJIJhO.o: In function `main':
main.cpp:(.text+0xad): undefined reference to `std::basic_istream<char, std::char_traits<char> >& operator>><int>(std::basic_istream<char, std::char_traits<char> >&, FeatureVector<int>&)'
main.cpp:(.text+0xba): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& operator<< <int>(std::basic_ostream<char, std::char_traits<char> >&, FeatureVector<int> const&)'
collect2: ld returned 1 exit status
The class definition:
common.h
#include <iostream>
using namespace std;
featurevector.h
#ifndef FEATURE_VECTOR_H
#define FEATURE_VECTOR_H
#include <common.h>
template < class FEAT_TYPE >
class FeatureVector;
template < class FEAT_TYPE >
istream & operator >> (istream &, FeatureVector<FEAT_TYPE> &);
template < class FEAT_TYPE >
ostream & operator << (ostream &, const FeatureVector<FEAT_TYPE> &);
template < class FEAT_TYPE >
class FeatureVector{
public:
FeatureVector(int = 0);
...
friend istream & operator >> <>(istream &, FeatureVector<FEAT_TYPE> & );
friend ostream & operator << <>(ostream &, const FeatureVector<FEAT_TYPE> &);
...
~FeatureVector();
private:
int m_nDim;
FEAT_TYPE * m_pFeat;
};
#endif
featurevector.cpp
#include <featurevector.h>
...
template < class FEAT_TYPE >
istream & operator >> (istream & input, FeatureVector< FEAT_TYPE> & refFeat ){
int d;
for(d=0; d < refFeat.getDim(); d++){
input >> refFeat.m_pFeat[d];
}
return (input);
}
template < class FEAT_TYPE >
ostream & operator << (ostream & output, const FeatureVector< FEAT_TYPE > & refFeat ){
int d;
for(d=0; d < refFeat.getDim(); d++){
output << refFeat.m_pFeat[d] << " ";
}
output << endl;
return (output);
}
...
#include "featurevector-impl.cpp"
featurevector-impl.cpp
template class FeatureVector<int>;
//template istream & operator >> <>(istream &, FeatureVector<int> &);
//template ostream & operator << <>(ostream &, const FeatureVector<int> &);
mylib.h
#ifndef MY_LIB_H
#define MY_LIB_H
#include <featurevector.h>
#endif
main.cpp
#include <mylib.h>
#include <common.h>
int main(){
FeatureVector<int> pFeat(10);
cin >> (pFeat);
cout << (pFeat);
return (0);
}
Makefile associated with "mylib"
INC=./inc
SRC=./src
LIB=./lib
OBJ=./obj
CC=g++
CFLAGS=-O3 -Wall
mylib: $(LIB)/mylib.a
echo "mylib was created!..."
$(LIB)/mylib.a:
$(OBJ)/featurevector.o
ar csr $(LIB)/mylib.a
$(OBJ)/featurevector.o
$(OBJ)/featurevector.o: $(SRC)/featurevector.cpp
$(CC) -c $(CFLAGS) $(SRC)/featurevector.cpp -I$(INC)
-o $(OBJ)/featurevector.o
clean:
rm -rf $(LIB)/*.a
rm -rf $(OBJ)/*.o
Makefile for main.cpp (the main.cpp with its Makefile are under an "app" directory)
LIB=../lib
INC=../inc
OBJ=../obj
BIN=../bin
CC=g++
CFLAGS=-O3 -Wall
LFLAGS=-lmylib -lm
[email protected]: $(LIB)/mylib.a [email protected]
cd ..; make; cd app;
$(CC) $(CFLAGS) [email protected] -o $(BIN)/$@ -I$(INC) -L$(LIB) $(LFLAGS)
clean:
rm -rf $(BIN)/*
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