Hi, I'm getting different behaviours using is_base_of on different compilers (tested with gcc, icc, xlc). #include #include struct A { }; struct B : public A { }; int main() { // Compile fine under all compilers BOOST_STATIC_ASSERT( (boost::is_base_of::value) ); // all fail in xlC 10.1, work fine in gcc 4.3-4.4 and icc 11 BOOST_STATIC_ASSERT( (boost::is_base_of::value) ); BOOST_STATIC_ASSERT( (boost::is_base_of::value) ); BOOST_STATIC_ASSERT( (boost::is_base_of::value) ); // Compile fine under all compilers BOOST_STATIC_ASSERT( (boost::is_base_of::value) ); BOOST_STATIC_ASSERT( (boost::is_base_of::value) ); BOOST_STATIC_ASSERT( (boost::is_base_of::value) ); BOOST_STATIC_ASSERT( (boost::is_base_of::value) ); return 0; } Thanks