In fileobject the mode string is sanitized using  a function, sanitize_the_mode().

The same thing needs to happen for posixmodule.fdopen().  Otherwise, the universal_newlines regression test in test_subprocess.py will fail for python compiled with Visual Studio 2005.

I have made a local patch by copying this static function over, and it fixes the issue, but I wonder if we would want to share this code?  Also, are there other places that spring to mind where we have to sanitize mode strings before handing them to fopen-like functions?

Kristján