Hello I have the following simple code, but doesn't get compiled: #define DECLARE_PTR_AUTO_DELETOR_CONDITIONAL(CLASS, VAR_PTR, CONDITION)\ boost::scoped_ptr<CLASS> auto__deletor__for__ ## VAR_PTR (\ boost::lambda::ret(boost::lambda::if_then_else(_1,\ VAR_PTR, static_cast(0)))(static_cast<bool>(CONDITION))) struct B { B() { std::cout << _T("\nCalling B::B()"); } ~B() { std::cout << _T("\nCalling B::~B()"); } }; bool processB(B *pb, bool accept) { if(accept) if(pb) { std::cout << _T("\nDeleting B by processB()"); delete pb; } return accept; } void test_selector() { bool result; B *pb1 = new B(); result = processB(pb1, true); // delete by processB DECLARE_PTR_AUTO_DELETOR_CONDITIONAL(B, pb1, (result == false)); B *pb2 = new B(); result = processB(pb2, false); // you do the job! DECLARE_PTR_AUTO_DELETOR_CONDITIONAL(B, pb2, (result == false)); } int main() { test_selector(); } Thanks for any help. B/Rgds Max ------------------------------------------------------------------- 新浪空间——与朋友开心分享网络新生活！(http://space.sina.com.cn/ )