I used the regex library from version 1.28.0 with BCB6. I was able to have a single function CommentsStrings::MatchFound(boost::match_result<std::string::const_iterator> what); to process both a std::string and a boost::mapfile. The calling functions are: //--------------------------------------------------------------------------- void CommentsStrings::Analyse(const std::string& Buffer) { Buffer_ = Buffer; AllCommentsStrings_.clear(); // find comments and strings std::string::const_iterator start, end; start = Buffer_.begin(); end = Buffer_.end(); boost::regex_grep( std::bind1st(std::mem_fun(&CommentsStrings::MatchFound), this), start, end, CommentStringExpression); } //--------------------------------------------------------------------------- void CommentsStrings::Analyse(const char *file) { currentFile = file; AllCommentsStrings_.clear(); // find comments and strings boost::mapfile f(currentFile.c_str()); boost::mapfile::iterator start, end; start = f.begin(); end = f.end(); boost::regex_grep( std::bind1st(std::mem_fun(&CommentsStrings::MatchFound), this), start, end, CommentStringExpression); } Now I am using BDS2006 and boost 1_33_1 I am getting an error Could not find a match for 'std::bind1st<std::mem_fun_t<bool,CommentsStrings,smatch> >::operator ()(cmatch)'. I know that the iterator for std::string is a class and not a char pointer. I am at a loss as how to proceed. John.