Question

Suppose I have a function template where the type parameter is used as a return type only:

template <typename T>
T foo()
{
    return whatever;
}

Then what is the correct syntax to specialize that function template? Both of the following seem to work:

template <>
std::string foo()
{
    return whatever;
}

template <>
std::string foo<std::string>()
{
    return whatever;
}

Is there any difference between the two? If not, what is the idiomatic way?

Answer 1

The compiler will deduce the correct template specialization based on informations provided (here, the function return type).

So these syntaxes have exactly the same behaviour, one being more explicit than the other.