Strange C++ template Syntax

Question

In an Article The case for D I saw this C++ expression:

object.template fun<arg>()

can anyone explain it?

EDIT: Thanks Mark, I see now that is is indeed a duplicate. But as it is just a side note in a long more comprehensive answer I will just condense the specific answer here in an example.

#include <iostream>
using namespace std;

template <typename T>
struct A
{
        T y;
        void write()
        {
                y.T::template print<int>(); // GOOD:  I have seen often 
                y.template print<int>();    // GOOD:  shortcut, I did not know
                y.print<int>();             // ERROR: I have seen this work on old compiler
        }
};
struct B
{
        template <typename T>
        void print() {cout << "print b" << endl;}
};
int main ()
{
        A<B> a;
        a.write();
}