Using Como 4.3.9 Beta, I get the following errors in Boost Regex: "....\boost/regex/v4/fileiter.hpp", line 331: error #135: namespace "std" has no member "ptrdiff_t" typedef std::ptrdiff_t difference_type; ^ "....\boost/regex/v4/fileiter.hpp", line 378: error #135: namespace "std" has no member "ptrdiff_t" typedef std::ptrdiff_t difference_type; ^ I had similar errors in Boost Filesystem. Isn't Boost tested with Como C++? I find testing with Como invaluable for my own code, there are many errors that only Como catches. Please fix! Emil Dotchevski