template definitions syntax

Question

Short question, are these definitions same?

1.

    template<class T1>
    template<class T2>
    void function(T1 *a, T2*b);

2.

    template<class T1,class T2>
    void function(T1 *a, T2*b);

Answer 1

No they are not the same. The first case won't compile as a free function(live example). Normally you would do the first case when you have a template class and you have a function in it that takes another template parameter

template <typename T1>
class Foo
{
public:
    template<typename T2>
    void function(T1 *a, T2*b);
};

template<class T1>
template<class T2>
void Foo<T1>::function(T1 *a, T2*b);

Your second example is just fine as a function with two template parameters.