/Za compiler directive does not compile system headers in VS2010

Question

I wanted to disable language extensions to be able to do some tests in my project. I found that I must set /Za compiler directive from http://msdn.microsoft.com/en-us/librar

Answer 1

The windows headers have never compiled with /Za.

There are other problems as well with /Za, that has caused Microsoft to stop testing their C++ standard library with that option. As told here:

http://permalink.gmane.org/gmane.comp.lib.boost.devel/212180

The recommendation is not to use it in "real" code.