I am just starting out with C++, and ran into this problem. I have a class Fifo defined in Fifo.h:
/* Fifo.h */
#ifndef FIFO_H_
#define FIFO_H_
#include <atomic>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
template <class T>
class Fifo
{
public:
Fifo<T>(int len);
~Fifo<T>();
int AddTokens(T* buffer, int len);
int RetrieveTokens(T* buffer, int len);
private:
//int len;
};
#endif /* FIFO_H_ */
And the definitions in Fifo.cpp:
/* Fifo.cpp*/
#include "Fifo.h"
template <class T>
Fifo<T>::Fifo(int len)
{
//_fifoptr = new FifoImpl_class((T)len);
printf ("From the constructor\n");
//thisbuffer = malloc(sizeof(T)*len);
}
template <class T>
Fifo<T>::~Fifo() { }
template <class T>
int Fifo<T>::AddTokens(T* buffer, int len)
{
printf("Added tokens\n");
return(1);
}
template <class T>
int Fifo<T>::RetrieveTokens(T* buffer, int len)
{
printf("Removed tokens\n");
return(2);
}
And, I test my class like this (Fifotest.cpp):
#include "Fifo.h"
int main(int argc, char *argv[])
{
Fifo<int> MyFifo(20);
}
Building it with gcc-4.5 gives me this error:
undefined reference to Fifo<int>::~Fifo()'
undefined reference toFifo::Fifo(int)'
Looks like I have the relevant methods defined, but I am not able to figure out why I get this error. I spent time googling for it, and the option was to take a running class and modify it. But then, I want to know what is wrong with what I already have. Would appreciate any help!
