I'm getting the following warning just by including the <boost/date_time/posix_time/posix_time.hpp> header file in my msvc express 2008 project: c:\program files (x86)\microsoft visual studio 9.0\vc\include\iosfwd(607) : warning C4996: 'std::char_traits<char>::copy': Function call with parameters that may be unsafe - this call relies on the caller to check that the passed values are correct. To disable this warning, use -D_SCL_SECURE_NO_WARNINGS. See documentation on how to use Visual C++ 'Checked Iterators' I know that the reason why it's giving me the warning is self explanatory but boost headers aren't supposed to give us warnings. In fact, the warning is not even in the boost header file, but it seems to be included/caused by it. I just want to know if I'm doing something wrong or this is the MSVC header that is messed up. Thanks, André.