syntax2.c

this is a gcc file, you can download it and learn its usetility, for further detail please look at t

// Build don't link:

// Copyright (C) 2000 Free Software Foundation, Inc.
// Contributed by Nathan Sidwell 22 June 2000 <[e-mail]>

// Origin GNATS bug report 262 from Jeremy Sanders <[e-mail]>
// and several others. With templates, it's very easy to say something
// erroneous like
//    template class X::X<whatever>
// The culprit
//    ... class X::X ...
// caused us to ICE as we got confused about pushing and popping scopes.

template <class T> class image
{
public:   
  template <class U> image(const image<U> &copy);
};

template <class T> template <class U> image<T>::image(const image<U> &copy)
{
}

template class image<double>;
template class image<double>::image (const image<int> &); // ERROR - parse error
template class image<double>::image (image<int>); // ERROR - specified as declarator-id
template image<double>::image (const image<int> &);