Explicit specialization of member function of a template class

Question

I have it:

template<class T, class U> class A { template<size_t N> void BindValues(); } template<class T, class U> template<size_t N> inline void A<T, U>::BindValues() { conn->setValue<N-1>( std::get<N-1>(m_Tuple) ); BindValues<N-1>(conn); } template<class T, class U> template<> inline void A<T, U>::BindValues<1>() { conn->setValue<0>( std::get<0>(m_Tuple) ); } 

My compilation error:

 invalid explicit specialization before '>' token enclosing class templates are not explicitly specialized template-id BindValues<1> for void A<T, U>::BindValues() does not match any template declaration 

Answer 1

Unfortunately, the template method inside the template class cannot be specialized solely on the basis of the template argument of the method.

You need to specialize the template class as well . In other words, the specialization of the member method should be a full specialization in the parameters of class template (i.e., <T,U> ), as well as the parameters of the template member (i.e., <size_t> ).

For example, you may need to specialize in this ( demo ):

 template<> // <------ you have to specialize class also template<> inline void A<int, double>::BindValues<1>() // <-------- see A<T,U> { ... } 

Answer 2

What you are trying to do is partial template specialization for a function that is not valid.

You can define a template function on N to specialize template A (for example, A<int, int>::BindValues<N>() ), but vice versa.