yes, the file relation of my test code is : main.C is placed in .../boost_1_35_0/test/ boost is in .../boost_1_35_0/ CC version : Forte Developer 7 C++ 5.4 Patch 111715-18 2006/11/02 and errors are : CC -g -I../. -c -o main.o main.C ".././boost/lambda/detail/function_adaptors.hpp", line 203: Error: Unexpected type name "boost::lambda::Arg1" encountered. ".././boost/lambda/detail/function_adaptors.hpp", line 203: Error: Cannot cast from int to boost::lambda::Result. ".././boost/lambda/detail/function_adaptors.hpp", line 210: Error: Template parameter boost::lambda::Func requires a type argument. ".././boost/lambda/detail/function_adaptors.hpp", line 202: Error: The type of specialized argument boost::lambda::Func is dependent on another argument. ".././boost/lambda/detail/function_adaptors.hpp", line 202: Error: Partial specialization parameter Arg1 is not used in the arguments. ".././boost/lambda/detail/function_adaptors.hpp", line 202: Error: Partial specialization parameter Result is not used in the arguments. ..................................... thanks. ------------------------------------------------------------------------ -------------------------------------- Can I just be absolutely clear here - Do you mean that compiling this code:- #include <boost/lambda/lambda.hpp> #include <iostream> #include <iterator> #include <algorithm> int main() { using namespace boost::lambda; } Gives you compile errors? Rob.