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From: SERAFINI%RAL@AMES-IO.ARPA
Newsgroups: comp.os.vms
Subject: VMS/RMS question
Message-ID: <8704250736.AA09643@ucbvax.Berkeley.EDU>
Date: Thu, 23-Apr-87 16:33:08 EDT
Article-I.D.: ucbvax.8704250736.AA09643
Posted: Thu Apr 23 16:33:08 1987
Date-Received: Sun, 26-Apr-87 19:58:37 EDT
Sender: daemon@ucbvax.BERKELEY.EDU
Distribution: world
Organization: The ARPA Internet
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info-vaxers,

I feel foolish for asking this question, but I've looked everywhere I know
and can't find a solution.  

How can I find out if a file is readable or writable given the current
process' priveleges?  I've tried F$File_Attributes to get the protection
string, but I found the gotcha that a file can have read protection set,
but the directory file that contains the file doesn't. Obviously, having to
check read protection on every directory in the path is a real hassle,
especially from DCL.  Is there some system service I don't know about
that combines all the processing necessary to achieve this? I know it's
non-trivial, and I assume that it's been done but I just haven't learned
yet.  The problem also exists for trying to write files.  Is there a better
solution than opening the file and testing for failure?

Thanks much.
Dave Serafini
Sterling Software 
NASA/Ames Research Center

serafini%ral@ames-io.arpa   or RAL::SERAFINI (SPAN node 24.6)