Re: legal C++ code (use of templates with parameters)?
On Jul 20, 2:11 am, "a...@atai.org" <licheng...@gmail.com> wrote:
A question on C++:
Is the following legal C++ code?
No. And since it's not really clear to me what it is meant to
do, it's hard to say what changes would be necessary to make it
legal.
typedef int (*func)(int);
template <class A>
class D1
{
public:
template <class B>
func f(void)
{
return A::some_func<B>;
What is A::some_func? I don't know, and neither does the
compiler. If it is supposed to be a member function template of
A, then 1) as others have pointed out, you need to add a keyword
template, and 2) the only things you can do with such member
functions is call them or take their address, and you do
neither.
return &template A::some_func<B>;
would be legal (I think), *if* A contained a static member
function named some_func, which took an int as argument, and
returned an int.
}
};
template <class A1, class B1>
func g(void)
{
return A1::m1<B1>;
}
The same issues as above. You have to tell the compiler that
A1::m1 is a template. (Otherwise, it assumes that the '<'
following it is a less-than operator.) And then you don't do
anything legal with the member function (assuming it is a member
function).
--
James Kanze