Question

struct A
{
    template <class U> 
    void f(U)
    {

    }
};

template <class T>
void f(T t) 
{
    A a;
    a.template f<int>(t);
    a.template f<>(t);
    a.f<int>(t);
    a.f<>(t);
    a.f(t);
}

At least under MSVC2010 the above code compile fine.

Among all the manners to call A.f is there any preferentials way to do this?

Is there any differences ?

Answer 1

Well, a has type A, which is not a dependent type in this context. So the template keyword is not needed and only serves to obfuscate the code — don’t use it.

The version that invokes a template without supplying any arguments, again does nothing to change behavior and only makes the code less readable — don’t use it either.

Between the two remaining candidates, a.f(t) and a.f<int>(t), use the first in most cases, and the second if the compiler fails to deduce the type.