How is unexpected() defined?

[Maurizio Loreti]

Hello - the current standard states that, if a procedure declares the
exceptions that may be thrown and throws an exception not declared, the
procedure unexpected() is called; and that in turn unexpected() may
throw, or call terminate().

I was playing with the following toy code:

#include <iostream>
#include <stdexcept>

void fun() throw() {
  std::cout << "In fun()\n";
  throw std::runtime_error("ahi ahi");
}

int main() {
  try{
    fun();
  } catch (std::exception &e) {
    std::cout << "Exception: \"" << e.what() << "\"\n";
  }
  return 0;
}

namespace std {
  void unexpected() {
    cout << "In unexpected()\n";
    throw;
  }
};

Compiled and linked with KCC does what is expected, i.e.:
In fun()
In unexpected()
Exception: "ahi ahi"

Compiled and linked with g++ 3.0.2 it does not:
In fun()
Aborted (core dumped)

Looking at the core file with gdb:
MLO@mlinux 14 $ gdb ./foo core
GNU gdb 5.0
...
(gdb) where
#0  0x400b8d41 in __kill () from /lib/libc.so.6
#1  0x400b89b6 in raise (sig=6) at ../sysdeps/posix/raise.c:27
#2  0x400ba0d8 in abort () at ../sysdeps/generic/abort.c:88
#3  0x40045685 in _ZN10__cxxabiv111__terminateEPFvvE (
    handler=0x400ba010 <abort>)
    at ../../../../gcc-3.0.2/libstdc++-v3/libsupc++/eh_terminate.cc:47
#4  0x400456c0 in _ZN10__cxxabiv112__unexpectedEPFvvE (
    handler=0x400456c0 <_ZN10__cxxabiv112__unexpectedEPFvvE>)
    at ../../../../gcc-3.0.2/libstdc++-v3/libsupc++/eh_terminate.cc:57
#5  0x400456d5 in _ZN10__cxxabiv112__unexpectedEPFvvE (
    handler=0x400456a0 <_ZSt9terminatev>)
    at ../../../../gcc-3.0.2/libstdc++-v3/libsupc++/eh_terminate.cc:63
#6  0x4004558a in __cxa_call_unexpected (exc_obj=0x804f208)
    at ../../../../gcc-3.0.2/libstdc++-v3/libsupc++/eh_personality.cc:417
#7  0x804a552 in _Z3funv ()
#8  0x804a56e in main ()
#9  0x400b29cb in __libc_start_main (main=0x804a560 <main>, argc=1,
    argv=0xbffff9d4, init=0x804a044 <_init>, fini=0x804c970 <_fini>,
    rtld_fini=0x4000ae60 <_dl_fini>, stack_end=0xbffff9cc)
    at ../sysdeps/generic/libc-start.c:92
(gdb)

shows that something like unexpected is called
("_ZN10__cxxabiv112__unexpectedEPFvvE"), with a signature different
from my own unexpected().  Grepping the include files for 'unexpected'
shown nothing.

The questions are:
1) what g++ exactly does in these situations?
2) the g++ behavior is not standard, is it?  If it were, *my*
   unexpected had to be called.
3) what am I supposed to do (command line options, ...) in order to
   force g++ to a standard behavior?

                Thank you in advance,           M.

-- 
Maurizio Loreti                         http://www.pd.infn.it/~loreti/mlo.html
Univ. of Padova, Dept. of Physics - Padova, Italy            loreti@pd.infn.it