Function Templates

You can't partially specialize a function template. You can only partially specialize a class template.

A class template is a template; a template class is an instantiation of a class template. A function template is a template; a template function is an instantiation of a function template.

References:
  More Exceptional C++ by Herb Sutter. Addison-Wesley, 2001, p. 66.
  http://womble.decadentplace.org.uk/c++/template-faq.html#phrase-order