Hi, I'm trying merge some code some of which uses a mixture of BB and BLL to just use the BLL under VC7.1. Having changed some 200 expressions without incident if find I can't see the wood for the trees here. The existing code, working with BB, is; typedef boost::function<void(ICollection*)> FECCFunc; void ForEachCollectionInChannels(IAmplifier* pIAmp,FECCFunc const & fec); typedef boost::function<void(IProperty*)> FEPFunc; void ForEachProperty(ICollection* pCollection,FEPFunc const & fep); void CalcPropCurValMaxWidth(IProperty* pProp,CColumnMap& map); ... void Problem() { CColumnMap m_ChanCols; IAmplifier* pIAmp; ForEachCollectionInChannels(pAmp,bind(ForEachProperty,_1,cref(bind(&CalcProp CurValMaxWidth,_1,ref(m_ChanCols)))); //Here } What's the equivalent with using BLL? Thanks, Richard.