My 'template' does not compile

[tonnot]

I have
.h file

template <class T>
std::string formato(T number, string format);
template <class V>
QString Qformato(V number, string format);

and at cpp:

template <class T>
std::string formato(T number, string format)  {
  return "....";
}
template <class V>
QString Qformato(V number, string format)  {
  return QString::fromStdString(formato(number,format));
}

And i have :
undefined reference to `QString Qformato<int>(int, std::string)'

What I'm doing bad? Maybe I cannot have templates with h and cpp??
Thanks

[hanst99]

Do you include the header file in the cpp file? Do you compile the cpp file (not the h file)? Is formato also a template (it won't work if it's not a template or overloaded for the possible arguments).

[moorecm]

What I'm doing bad? Maybe I cannot have templates with h and cpp??

Basically no, you cannot have template definitions in source (.cpp) files. This is in accordance with The Inclusion Model¹. Move the template function definitions into the header file and give that a try.


¹ I don't want to get into the different models at this time; just know that there are other (less popular) ways to deal with templates.