Ok, I've determined that the memory leak I was seeing is real, atleast in
vc7.1. The boost::detail::sp_counted_base_impl<P,D> held by a serialization
loaded shared_ptr never gets deleted. This is due to
boost::serialization::load_construct_data setting weak_count to 0. When the
sp_counted_base::weak_release() gets called new_weak_count is -1 so destruct
is not called.
A fix that works for my application, is to comment out the line:
shared_ptr_access::weak_count(*t) = 0;
in
template<class Archive, class P, class D>
inline void load_construct_data(
Archive & ar,
boost::detail::sp_counted_base_impl<P, D> * t,
const unsigned int /* file_version */
The following was used to reproduce the problem in vc7.1.
// SerializationSharedPtrTest.cpp : Defines the entry point for the console
application.
//
#define CRTDBG_MAP_ALLOC
#include <stdlib.h>
#include <crtdbg.h>
struct Checker
{
Checker()
{ _CrtSetDbgFlag( _CRTDBG_ALLOC_MEM_DF
| _CRTDBG_CHECK_ALWAYS_DF
| _CRTDBG_LEAK_CHECK_DF );
}
};
Checker lChecker;
#include <boost/serialization/shared_ptr.hpp>
#include <boost/archive/text_oarchive.hpp>
#include <boost/archive/text_iarchive.hpp>
#include <fstream>
typedef std::string tName;
class PointedToClass
{
int mInt;
friend class boost::serialization::access;
template< class Archive > void serialize( Archive &ar, unsigned int
version )
{
ar & boost::serialization::make_nvp( "Int", mInt );
}
public:
~PointedToClass(){}
PointedToClass():mInt(123){}
PointedToClass( int aInt ):mInt( aInt){}
PointedToClass( const PointedToClass& aRhs ):mInt(aRhs.mInt){}
};
typedef boost::shared_ptr< PointedToClass > tPtr;
int main( int argc, char* argv[] )
{
{
std::ofstream lOut( "SomeClass.archive", std::ios_base::out |
std::ios_base::trunc );
if( lOut.good() )
{
boost::archive::text_oarchive oa( lOut );
tPtr lPtr( new PointedToClass(456) );
oa << boost::serialization::make_nvp( "Ptr" , lPtr );
}
}
{
std::ifstream lIn( "SomeClass.archive" );
tPtr lPtr;
if( lIn.good() )
{
boost::archive::text_iarchive ia( lIn );
ia >> boost::serialization::make_nvp( "Ptr" , lPtr );
}
}
return 0;
}
