Re: [boost] Re: [math constants] VC++ experts needed :)

From: Bronek Kozicki (brok_at_[hidden])
Date: 2004-03-11 02:10:39

Daniel Frey <d.frey_at_[hidden]> wrote:
[...]

I tried following code:

#include <iostream>
template <typename T> class V {};
template <template <typename> class T> struct B {};
struct D : B<V> {};
template <typename T>
void f (const B<T>&)
{
 std::cout << typeid(T).name() << std::endl;
}
int main()
{
  D d;
  f (d);
}

According to Comeau compiler and GCC this program is invalid. I have
following error messages
(from GCC 3.3.1):
T246.cpp:6: error: type/value mismatch at argument 1 in template
parameter list
   for `template<template<class> class T> struct B'
T246.cpp:6: error:   expected a class template, got `T'
T246.cpp:7: error: ISO C++ forbids declaration of `parameter' with no
type
T246.cpp: In function `int main()':
T246.cpp:13: error: no matching function for call to `f(D&)'

(from Comeau online 4.3.3 beta)
"ComeauTest.c", line 6: error: template parameter "T" is not a class
template
  void f (const B<T>&)
                  ^
"ComeauTest.c", line 13: error: no instance of function template "f"
matches the
          argument list
            The argument types that you used are: (D)
    f (d);
    ^

... however it compiles under VC71, and the output of this program is:
class V

I think that's a surprise?

B.