Hello, the remaining two failures for Tru64/CXX (kolmogorov_max_flow_test and max_flow_test) should be marked as expected, as the STL implementation on this platform seems to suffer from a vector<bool>::iterator which doesn't satisfy all requirements: cxx: Error: ../boost/concept_check.hpp, line 553: no operator "+" matches these operands (nomatoprfun) operand types are: std::iterator_traits<std::vector<bool, std::allocator<bool>>::iterator>::difference_type + std::vector<bool, std::allocator<bool>>::iterator ... i = i + n; i = n + i; // require addition with difference type ---------------------------^ If agreed, either me or the author can do the markup, whichever is preferred. Markus