I've found that using the /Za option breaks a lot of things for using boost. I believe we've gone a bit overboard in our requirements for MSVC for example, all of my date_time stuff works JUST fine....even using /Za if I simply add a line to auto_link.hpp which will accept _MSC_VER >= 1310
I note that another test from a colleague (boost threads) won't compile if /Za is turned on. the visualc.hpp file in config turns off the Win32API if extensions aren't enabled. Say what?? what do the language extensions have to do with libraries being called?
The problem is that with /Za you can't compile <windows.h> (or at least not last time I checked), there is also an assumption that libraries are compiled with the same options as your code, I appreciate that in some limited cases that isn't always a requirement, but it usually is.... John.