I have two functions which swap elements between ptr_vectors. The first compiles and apparently works correctly. typedef boost::ptr_vector<Gene> GeneVectType; GeneVectType geneVect; void Gene::swapGene(Gene* other) { geneVect.transfer(geneVect.end(), other->geneVect.begin(), other->geneVect); other->geneVect.transfer(other->geneVect.end(), geneVect.begin(), geneVect); } Occasionally I must reverse the swap with this unswap function. void Gene::unswapGene(Gene* other) { // The line below is line 560 referred to in the error message. geneVect.transfer(geneVect.begin(), other->geneVect.rbegin(), other->geneVect); other->geneVect.transfer(other->geneVect.begin(), geneVect.rbegin(), geneVect); } This function should take the last element from each container and transfer it to the beginning of the other container. The unswapGene function will not compile. Here's the compiler message. C:\Boost SVN\trunk\boost/range/const_iterator.hpp(37) : error C2039: 'const_iterator' : is not a member of 'boost::reverse_iterator<Iterator>' with [Iterator=boost::void_ptr_iterator<std::_Vector_iterator<void *,std::allocator<void *>>,genprg::Gene>] C:\Boost SVN\trunk\boost/mpl/eval_if.hpp(63) : see reference to class template instantiation 'boost::range_const_iterator<C>' being compiled with [C=boost::reverse_iterator<boost::void_ptr_iterator<std::_Vector_iterator<void *,std::allocator<void *>>,genprg::Gene>>] C:\Boost SVN\trunk\boost/range/iterator.hpp(63) : see reference to class template instantiation 'boost::mpl::eval_if_c<C,F1,F2>' being compiled with [C=true, F1=boost::range_const_iterator<boost::reverse_iterator<boost::void_ptr_iterator<std::_Vector_iterator<void *,std::allocator<void *>>,genprg::Gene>>>, F2=boost::range_mutable_iterator<const boost::reverse_iterator<boost::void_ptr_iterator<std::_Vector_iterator<void *,std::allocator<void *>>,genprg::Gene>>>] C:\Boost SVN\trunk\boost/ptr_container/ptr_sequence_adapter.hpp(458) : see reference to class template instantiation 'boost::range_iterator<C>' being compiled with [C=const boost::reverse_iterator<boost::void_ptr_iterator<std::_Vector_iterator<void *,std::allocator<void *>>,genprg::Gene>>] ..\..\..\..\GSSTA\gene.cpp(560) : see reference to function template instantiation 'void boost::ptr_sequence_adapter<T,VoidPtrSeq,CloneAllocator>::transfer<genprg::Gene::GeneVectType,boost::reverse_iterator<Iterator>>(boost::void_ptr_iterator<VoidIter,T>,const Range &,PtrSeqAdapter &)' being compiled with [T=genprg::Gene, VoidPtrSeq=std::vector<void *,std::allocator<void *>>, CloneAllocator=boost::heap_clone_allocator, Iterator=boost::void_ptr_iterator<std::_Vector_iterator<void *,std::allocator<void *>>,genprg::Gene>, VoidIter=std::_Vector_iterator<void *,std::allocator<void *>>, Range=boost::reverse_iterator<boost::void_ptr_iterator<std::_Vector_iterator<void *,std::allocator<void *>>,genprg::Gene>>, PtrSeqAdapter=genprg::Gene::GeneVectType] Can anyone see what I'm doing wrong? -- Charles