Re: [boost] Serious problem with gcc 4 on Mac OS X, when using boost:shared_ptr

From: Peter Dimov (pdimov_at_[hidden])
Date: 2006-03-24 13:23:36

Ananda Tallur wrote:
> Hello,
>
> Originally, I had discovered a problem when using
> boost::unit_test_framework, for which I have already posted.
> But, by further analysing the problem, I could come out to a simple
> program, using only boost shared pointers, and which fails :
> -> on Mac OS X 10.4
> -> when compiled with gcc 4.0.1 (coming with XCode 2.2.1), or gcc 4.1
> (delivered by darwin ports)
> -> with optimisations : at least -O, or -O1, or -O2,etc... It works
> correctly with -O0
> -> using either boost 1.33.1, 1.33.0, or 1.32.0
>
> Below is the sample test program :
>
> --- macosx_gcc4problem.cpp ---

[...]

This issue has already been reported, along with a fix, by Howard Hinnant:

http://lists.boost.org/Archives/boost/2006/03/102088.php
http://lists.boost.org/Archives/boost/2006/03/102122.php
http://lists.boost.org/Archives/boost/2006/03/102134.php

and the upcoming 1.34 release will no longer suffer from it.

Thank you very much for taking the time to simplify the failing example. 
I've reformatted it a bit as a test case. If you verify that it still fails 
for you, I'll include it in the regression tests.

#include <boost/shared_ptr.hpp>
#include <boost/detail/lightweight_test.hpp>

struct A
{
    int value;
};

struct B
{
    B( boost::shared_ptr<A> val ): a( val ) {}

    boost::shared_ptr<A> a;
};

struct C
{
    C( B val ): b( val ) {}

    B b;
};

struct D
{
    D( C val ): c( val ) {}

    C c;
};

D create()
{
    boost::shared_ptr <A> a( new A );

    a->value = 12345;

    return D( C( B( a ) ) );
}

int main()
{
    D d = create();

    BOOST_TEST( d.c.b.a->value == 12345 );

    return boost::report_errors();
}