I think I have found the source of the internal compiler errors currently preventing boost.test to work with the toolset tru64cxx65. The following small sample fails to compile and gives me an internal compiler error when compiled with cxx. ---%<--- #include <boost/test/detail/basic_cstring/basic_cstring.hpp> using namespace boost::unit_test; // void foo(const_string const & s) // ok void foo(const_string s) // not ok { } int main() { foo(literal_string("foo")); return 0; } --->%--- Changing the declaration of foo() makes the compiler error go away. I'm currently thinking that the compiler perhaps has problems with the automatically generated copy constructors for the class basic_cstring. I tried writing an explicit copy constructor for basic_cstring but this doesn't seem to help. The compiler still crashes. Maybe someone else working with this platform has any ideas... Markus