Re: May be it's a std::map bug

From:
"Igor Tandetnik" <itandetnik@mvps.org>
Newsgroups:
microsoft.public.vc.stl
Date:
Wed, 23 Jul 2008 16:03:54 -0400
Message-ID:
<OlLdO9P7IHA.1592@TK2MSFTNGP04.phx.gbl>
lxxxk <lxxxk@discussions.microsoft.com> wrote:

It seems like that when I remove an element(A) from a std::map, I
can't remove another element(B) while the element(A) has been
removing. For example:

class test
{
public:
   virtual ~test();

   std::string m_strVictim;
};

std::map< std::string, std::tr1::shared_ptr<test> > g_mapTests;

test::~test()
{
   g_mapTests.erase( m_strVictim );
}

int main(int argc, char* argv[])
{
   test* t1 = new test;
   t1->m_strVictim = "2";
   g_mapTests["1"] = std::tr1::shared_ptr<test>( t1 );
   g_mapTests["2"] = std::tr1::shared_ptr<test>( new test );
   g_mapTests.erase( "1" );

   return 0;
}


17.4.4.5/1 Which of the functions in the C++ Standard Library are not
reentrant subroutines is implementation-defined.

Though I suspect the standard doesn't have this kind of reentrancy in
mind, but rather a reentracy though signal handler. The term "reentrant
subroutine" is never defined.

Personally, this code looks like a disaster to me. I wouldn't have
expected it to ever work on any implementation, except by accident.
--
With best wishes,
    Igor Tandetnik

With sufficient thrust, pigs fly just fine. However, this is not
necessarily a good idea. It is hard to be sure where they are going to
land, and it could be dangerous sitting under them as they fly
overhead. -- RFC 1925

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