Consider m_files to be a vector of pointers to boost::filesystem::pathS: std::partition( m_files.begin(), m_files.end(), boost::bind( &boost::filesystem::is_directory, *boost::lambda::_1 ) ); I want to invoke is_directory on the pointees. The error message is extremely long-winded and expands over several pages. I suppose you don't want to see it :) But maybe you can see immediately what I'm doing wrong? -- Matthias Kaeppler