id,summary,reporter,owner,description,type,status,milestone,component,version,severity,resolution,keywords,cc
8512,set member_hook access violation,toby_toby_toby@…,Ion Gaztañaga,"Visual Studio 2012 express, all patches. 32 bits.

Iterator dereference returns wrong pointer (offset by 4 bytes from normal).

I think it's because of virtual inheritance, mistake in offset_from_pointer_to_member (intrusive/detail/parent_from_member.hpp)

Output of program below:
>>>
offsets: 4 and 8
pointers: 00BEF94C and 00BEF948
<<<





#include <iostream>
#include <string>
#include <boost/noncopyable.hpp>
#include <boost/intrusive/set.hpp>

namespace intrusive = boost::intrusive;

class object : public boost::noncopyable
{
public:
    object()
	{
	}
    virtual ~object()
	{
	}
};


class signal : virtual public object
{
public:
	signal()
	{
	}
	virtual ~signal()
	{
	}
};


class record : public signal
{
public:
    record()
	{
	}
    virtual ~record()
	{
	}

public:
	virtual const std::string& get_buffer() const
	{
		return m_buffer;
	}

	typedef intrusive::set_member_hook<
		intrusive::link_mode<intrusive::auto_unlink>
		> hook;
	hook m_hook;

	std::string m_buffer;
};


template <class T, class M, M (T::*V)>
struct member_comparator
{
    bool operator()(const T& t1, const T& t2) const
    {
        return (t1.*V) < (t2.*V);
    }
    bool operator()(const M& m, const T& t) const
    {
        return m < (t.*V);
    }
    bool operator()(const T& t, const M& m) const
    {
        return (t.*V) < m;
    }
};

typedef member_comparator<
    record,
    std::string,
    &record::m_buffer
    > record_comparator;

typedef intrusive::set<
    record,
    intrusive::compare<record_comparator>,
    intrusive::member_hook<
        record,
        record::hook,
        &record::m_hook
        >,
    intrusive::constant_time_size<false>
    > records
    ;


int main(int argc, char** argv)
{
	union
	{
		int32_t as_int;
		const record::hook record::* ptr_to_member;
	}
	sss;
	sss.ptr_to_member = &record::m_hook;

	std::cout << ""offsets: "" << sss.as_int << "" and "" << offsetof(record,m_hook) << std::endl;

	records rr;

	std::string key = ""123"";
	records::insert_commit_data icd;
	std::pair<records::iterator,bool> ir = rr.insert_check(
		key,
		record_comparator(),
		icd
		);

	if ( !ir.second )
	{
		throw std::exception();
	}

	record rec;
	rec.m_buffer = key;
	records::iterator i = rr.insert_commit( rec, icd );

	record* rrr = &(*i);

	std::cout << ""pointers: "" << ((void*)rrr) << "" and "" << ((void*)&rec) << std::endl;

	return 0;
}
",Bugs,closed,To Be Determined,intrusive,Boost 1.53.0,Showstopper,wontfix,,