space() function requires a directory path on Windows #73
Description
I'm not sure whether this is a bug or a documentation issue.
On Windows, the filesystem::space call passes its parameter to GetDiskFreeSpaceEx, which is documented as requiring a directory.
The boost documentation makes no such requirement, and just talks about posix fstatvfs, which will accept a file.
So I think either the documentation needs updating to require a directory path, or the Windows code path needs to detect whether the parameter is a file and if so, strip the file name before calling GetDiskFreeSpaceEx.