This little piece of code, #include <algorithm> #include <functional> template <typename InputIterator, typename Predicate> inline bool if_all( InputIterator first, InputIterator last, Predicate predicate ) { return std :: find_if( first, last, std :: not1( predicate ) ) == last; } #include <vector> #include "boost/lambda/lambda.hpp" int main( ) { using namespace boost :: lambda; std :: vector<int> v; if_all( v.begin( ), v.end( ), _1 == 3 ); return 0; } Gives a compiler error, which I think tells me that my lambda expression, _1 == 3 does not provide the argument_type typedef. I thought lambda expressions were careful to to do this. What am I doing wrong? Thanks, Rob. -- ACCU - Professionalism in programming - http://www.accu.org