user-defined messages facet

[awlaframboise at aol dot com]

hello,

i'm trying to use a user-defined messages facet that derives from std::messages, in the manner described in bjarne's book (D.4.7).  however, i'm having some difficulties, and the manual at http://gcc.gnu.org/onlinedocs/libstdc++/22_locale/messages.html didnt discuss using the messages facet this way.

i'm using the latest snapshot "gcc version 3.1 20020429 (prerelease)" on i686-pc-mingw32, Windows XP, MSYS 1.0.7.

Here is my test program:
-----
#include <iostream>
#include <locale>
#include <string>


class mymsgs : public std::messages<char> {
  public:
    explicit mymsgs(size_t = 0) {
    }

    virtual catalog do_open(const std::basic_string<char> &name,
      const std::locale &loc) const {

      std::cout << "do_open: " << name << ", " << loc.name() << '\n';

      return 2;
    }

    virtual string_type do_get(catalog cat, int set, int msgid,
      const string_type &dfault) const {

      std::cout << "do_get: " << cat << ", " << set << ", " << msgid
        << ", " << dfault << '\n';

      return std::string("mystring");
    }

    virtual void do_close(catalog cat) const {
      std::cout << "do_close: " << cat << '\n';
    }
};


int main() {
  const std::messages<char> &msgfacet = std::use_facet<mymsgs>(std::locale());

  std::messages<char>::catalog cat = msgfacet.open(std::string("myname"), std::locale());

  msgfacet.get(cat, 2, 3, std::string("mydefault"));

  msgfacet.close(cat);

  try {
    const mymsgs &test = dynamic_cast<const mymsgs &>(msgfacet);

    std::cout << "ok\n";
  }
  catch(...) {
    std::cout << "failed\n";
  }
}
-----

i invoke gcc with "g++ -Wall -W -ansi -pedantic -O0 -g3 -o mytest mytest.cpp" and only get one warning about the unused variable.  when i run it, i only get "failed" as output.  none of the print statements in the facet members are run, and apparently the facet is not actually my facet.

i cant figure out whats going wrong here: 1) gdb is kindof flakey on this target for some reason 2) i cant quite figure out the design of libstdc++-v3 locales..

can someone lend me some guidance?

AaronWL