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From: Robert A Duff <bobduff@shell01.TheWorld.com>
Subject: Re: if file exist
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Date: Thu, 26 Sep 2002 22:14:35 GMT
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"Warren W. Gay VE3WWG" <ve3wwg@cogeco.ca> writes:

> Nick Roberts wrote:
> > On 23 Sep 2002 06:38:22 -0600, Kilgallen@SpamCop.net (Larry Kilgallen)
> > strongly typed:
> >
> >>On some operating systems the existence of a file for which the user
> >>lacks read permission cannot be detected.  A general solution for
> >>detecting unreadable files is not possible.
> 
> On most file systems, when you don't have the permission(s)
> to read the _directory_, you cannot determine if the file
> exists or not (within that directory). This is because
> the directory itself is unreadable by you, and intentially
> so! So this is another example of how a general solution
> is not possible, and this applies to _most_ O/S in use,
> where security at the directory level is possible.

I don't agree that "a general solution is not possible".
A File_Exists return Boolean function makes perfect sense.
Of course it returns False if the file is invisible to the 
current process (because it "exists" in an inaccessible directory).
To *this* process, that file does not exist.

- Bob