The following code currently fails to compile because of a subtle interaction between bind-produced function objects and the current implementation of transform_iterator's 'dereference' function (the same applies to 'filter_iterator' and most likely the rest of the adaptors in the library): #include <boost/iterator/transform_iterator.hpp> #include <boost/bind.hpp> int add_two( int x ) { return x + 2; } int main() { int x[] = { 0 }; *boost::make_transform_iterator( boost::make_transform_iterator( x, boost::bind( &add_two, _1 ) ) , boost::bind( &add_two, _1 ) ); } The problem here is that the result of 'boost::bind( &add_two, _1 )' takes its argument by reference, while transform_iterator's 'dereference' implementation is: typename super_t::reference dereference() const { return m_f(*this->base()); } ^^^^^^^^^^^^^ In our case, '*this->base()' produces a temporary 'int' which cannot be directly passed to 'm_f'. Effectively, the issue prevents you from layering any iterator adaptors built with 'boost::bind' on top of 'transform_iterator', which, needless to say, is BAD. My sugesstion would be to replace the above with typename super_t::reference dereference() const { typename iterator_reference<Iterator>::type x( *this->base() ); return m_f( x ); } Comments? -- Aleksey Gurtovoy MetaCommunications Engineering