Ubuntu C++ explicit instantiation

[kinslayer_e]

Hi! I'm running Ubuntu 9.04 and using Code::Blocks as C++ IDE. I have the following code:

Temp.h:

#ifndef TEMP_H_INCLUDED
#define TEMP_H_INCLUDED

template <typename T>
class Temp {
    public:
        Temp (T d = T(0)): _dato(d) {}

        T    getDato () const;
        void setDato (T d);
    private:
        T _dato;
};

template class Temp<double>;

#endif // TEMP_H_INCLUDED

Temp.cpp:

#include "Temp.h"

template <typename T>
T Temp<T>::getDato () const { return _dato; }

template <typename T>
void Temp<T>::setDato (T d) { _dato = d; }

main.cpp:

#include "Temp.h"
#include <iostream>

using namespace std;

int main()
{
    Temp<double> temp(3.24);

    cout << temp.getDato() << endl;
    return 0;
}

As you can see, I'm trying to use explicit instantiation of the template in the header file, but when I try to compile, the linker shows me "undefined reference to Temp<double>::getDato() const".
The weird thing is that this code works in Windows with MinGW and GCC. In Ubuntu, it works if I put the template instantiation on the end of the Temp.cpp file.
I know I can / should put all the template's implementation on the header file and that will work, but this is for an university's work and they ask me to separate the implementation.

I'll apreciate any help or explanation!

[Rubberman]

This is pretty bogus usage/implementation of templates. FWIW, you really need to make sure that all template code instantiation is inline. The compiler needs to see the implementation at the point you use it. That it worked on some C++ implementations is just plain luck.

[kinslayer_e]

Sorry, I didn't understand what you mind with this "you really need to make sure that all template code instantiation is inline".
I know that this is not the best way of use templates, but is the way the teachers want, and it's hard to make them understand it. Specially because, AFAIK, there isn't a "standard" way for this.

(PD: Sorry if my english is not correct, I'm from Argentina)

[Rubberman]

Sorry, I didn't understand what you mind with this "you really need to make sure that all template code instantiation is inline".
I know that this is not the best way of use templates, but is the way the teachers want, and it's hard to make them understand it. Specially because, AFAIK, there isn't a "standard" way for this.

(PD: Sorry if my english is not correct, I'm from Argentina)

As the old saying goes, "Those who can, do. Those who can't, teach."...

[cgrebeld]

You could seperate the implementation into another header file like Temp_impl.h and then include it before the explicit instantiation.