The page <http://www.python.
org/doc/current/lib/os-file-dir.html> says the following 
about the function os.chmod:

chmod(path, mode) 
Change the mode of path to the numeric mode. 
Availability: Unix, Windows. 

The "mode" values are unclear.  It turns out that the 
UNIX file permission set (e.g., 0666 for read/writeable) 
works with the Windows set (where 0666 translates to  
33206).

Is it possible to describe the file permissions in more 
detail in the documentation at this point?

Attached is an email thread discussing this 
documentation issue.

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Could you try to produce a patch to improve the
documentation?  Or perhaps suggest better wording?

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Here's my first pass at some additional documentation.  My 
HTML skills are not up to par, but I've tried :)  I've attached 
the document separately.

m@

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Realistically, you should NEVER intentionally use chmod to set 
file permissions on Windows.  The FAT filesystem has no 
permissions, and NTFS has ACLs which are much too complex 
to map to a chmod style call.  MS only has chmod support so 
they can claim some level of posix compliance.

I'm not saying you should drop the ability to call os.chmod on 
windows, but perhaps the docs should say that its not the 
recommended way of doing things.  Unfortunately, there's not 
a recommended way of setting security that'll work on all 
Windows platforms either (although I'd start with os.popen
("cacls ...")  Even win32security requires some serious 
programming just to get started with manipulating ACLs.

Typical security looks something like this:

Microsoft Windows XP [Version 5.1.2600]
(C) Copyright 1985-2001 Microsoft Corp.

C:\Documents and Settings\grant>xcacls "\Program files"
C:\Program Files BUILTIN\Users:R
                 BUILTIN\Users:(OI)(CI)(IO)(special access:)
                                           GENERIC_READ
                                           GENERIC_EXECUTE

                 BUILTIN\Power Users:C
                 BUILTIN\Power Users:(OI)(CI)(IO)C
                 BUILTIN\Administrators:F
                 BUILTIN\Administrators:(OI)(CI)(IO)F
                 NT AUTHORITY\SYSTEM:F
                 NT AUTHORITY\SYSTEM:(OI)(CI)(IO)F
                 BUILTIN\Administrators:F
                 CREATOR OWNER:(OI)(CI)(IO)F


C:\Documents and Settings\grant>

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Well, let's not overreact here -- MS's _chmod simply calls the 
Win32 SetFileAttributes(), and the only thing it can change is 
the FILE_ATTRIBUTE_READONLY flag.  That's all part of 
Windows base services, and makes sense on FAT too.

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see patch 755677

sheesh neal, you couldn't patch this?  ;-)

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All I'm saying is that although chmod is valid windows call, it 
will not produce the effect that most users expect.  There's 
no harm in calling it, but it's not going to accomplish what 
most users want it to do.  This information is more important 
to a user than other inconsistencies in the Windows 
implementation.  (i.e. os.stat returning a value that is 
different than chmod set)

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Then please suggest the actual text you want to see in the 
docs.  I can't do it for you (for example, chmod has always 
done exactly what I've wanted it to do on Windows -- but 
then I've never wanted to do anything with it on Windows 
beyond fiddling the readonly bit).

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Tim-

I captured what Matthew Shomphe recommended into patch 755677
(http://www.python.org/sf/755677).  Hope this helps.

-c

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Something like:

"NOTE: Although Windows supports chmod, it incorporates 
much different functionality than a typical Unix user would 
expect.  Please refer to Microsoft’s documentation for more 
details."

would be nice.

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I think the wording suggested by logistix would be a good
addition to the docs.

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Added this note to the chmod docs:

Although Windows supports chmod, you can only set the
file's read-only flag with this function (via the
\code{S_IWRITE}
and \code{S_IREAD} constants or a corresponding integer value).
All other bits are ignored.

Doc/lib/libos.tex r1.164, r1.146.2.10.