http://bugs.winehq.org/show_bug.cgi?id=23355
--- Comment #6 from Chris Parker cparke@parkerfamily.name 2010-09-28 12:51:56 CDT --- (In reply to comment #2)
Bug #20887 also involves GetVolumeInformation. What controls whether GetVolumeInformationA("X:") succeeds or not is not GetCurrentDirectory(). It is the queried drive's default directory. MS-Windows maintains one default directory per drive letter (and per process) in the environment variable "=X:". You can see that by typing set " (including this double quote) in a DOS shell. It is only when the drive to be queried corresponds with the unique GetCurrentDirectory that the latter comes into play.
Not the case for a network drive share, any way. I'm in X:\ and run the Windows routine with just X: and it succeeds. I think all removable drive and media types don't require the trailing backslash. Why do we ever need to require the trailing backslash? (to validate a hard drive is real and fixed?)