Re: Is this error correct

From:

"John Carson" <jcarson_n_o_sp_am_@netspace.net.au>

Newsgroups:

microsoft.public.vc.language

Date:

Fri, 6 Apr 2007 16:06:08 +1000

Message-ID:

<#aAl3GBeHHA.4564@TK2MSFTNGP03.phx.gbl>

"mps" <mps@discussions.microsoft.com> wrote in message
news:BDAB1C6E-9000-4A3C-B6B1-D333EA83895F@microsoft.com

It appears that the problem is related to the default template
argument for vector because the following works fine:

#include <vector>

template <template <typename T, typename U> class X, typename T,
typename U> void f(X<T, U>) { }

int
main() {
std::vector<int> v;
f(v);
}

It seems clear that std::vector should be usable wherever a class
requiring one template argument is expected, so in the original
example, I believe the behavior of g++ is correct, while MSVC's behavior
is a bug.

vector is a template with two parameters. The fact that you only need to
explicitly provide one of them is a convenience but doesn't change the fact
that vector has two parameters and therefore is a different type from a
template that only has one parameter. Accordingly, your original code
involves types that don't match.

This is discussed in David Vandevoorde and Nicolai Josuttis, C++ Templates,
pp. 111-112.

You can also check that your original code does not compile with Comeau
online:

http://www.comeaucomputing.com/tryitout/

--
John Carson