Re: emacs's dired display of Window's file permission

[Xah Lee]

On Jun 22, 2:35 am, Eli Zaretskii <e...@gnu.org> wrote:
> > From: Xah Lee <xah...@gmail.com>
> > Newsgroups: gnu.emacs.help
> > Date: Sun, 21 Jun 2009 14:31:21 -0700 (PDT)
>
> > On Windows, how's emacs's dired display map the Window's file
> > permission?
>
> If by "Windows file permissions" you mean the native NTFS file
> security access rights, then Emacs on Windows currently doesn't look
> at them at all.  What Emacs shows you is the effect of a single mode
> bit: the read-only bit.  A file with the readonly bit set will be show
> with only read access, otherwise both read and write will be shown.
> The execute bit is _computed_ for executable programs and batch files.
>
> In addition, the single rwx group computed as I explain above is
> copied to the other 2 Posix groups, so, for example, a read-only
> non-executable file will be shown as "r--r--r--".
>
> > for example, emacs display this:
>
> >  -rw-rw-rw-  1 xah    None   814669 06-05 00:09 Snapshot_001.png
>
> In light of the above, I believe you will understand why.
>
> > however, cygwin termninal displays this:
>
> >  -rwx------+  1 xah    None   814669 Jun  5 00:09 Snapshot_001.png
>
> > The file's Properties shown in Explorer, has 3 group or users:
>
> >  SYSTEM
> >  xah
> >  Administrators
>
> Cygwin uses NT security features to emulate Posix owner/group/world
> standard access rights.  Emacs still doesn't.  We hope to add to Emacs
> support for Windows ACLs in a future release.  But even then, Emacs
> will not necessarily be compatible with Cygwin, because Posix
> emulation is not the most important goal of the native Windows port of
> Emacs.  In particular, Cygwin may do strange things with files whose
> ACL is not set by a Cygwin program, while the native Windows port of
> Emacs should work with these files as any other native Windows program
> does.
>
> If you want compatibility with Cygwin programs, use the Cygwin build
> of Emacs.

Thanks Eli. That's super helpful.

 Xah