Is this correct C++ code (Boost pool allocator with "const std::string" key)

From:

Roman W <bloody_rabbit@gazeta.pl>

Newsgroups:

comp.lang.c++.moderated

Date:

Tue, 8 May 2012 11:22:53 -0700 (PDT)

Message-ID:

<15226911.53.1336484440781.JavaMail.geo-discussion-forums@vbbh3>

{ reformatted; please limit your lines to 70 characters -mod }

The following code compiles under g++ 4.5.3, but does not under MS
Visual Studio 2008:

#include <map>
#include <boost/pool/pool_alloc.hpp>

int main()
{
    typedef const std::string key;
    typedef double* (*value)(const int&);
    std::map<key, value, std::less<key>,
boost::fast_pool_allocator<std::pair<const key, value> > >
        map_with_boost_allocator; // fails
}

(Boost version is 1.48). I've tracked the error to the compiler
thinking that these two lines in boost/pool/pool_allocator.hpp define
the same function:

static pointer address(reference r)
{
   return &r;
}
static const_pointer address(const_reference s)
{ return &s; }

Where "reference" and "const reference" are defined as

typedef value_type & reference;
typedef const value_type & const_reference;

In this case, "value_type" is "const K" where "K" == "const
std::string". Which compiler is correct:
g++ in accepting the code or MS Visual Studio 2008 in rejecting the
code?

Regards,
Roman

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