From:	CSBVAX::CSBVAX::MRGATE::"SMTP::CRVAX.SRI.COM::RELAY-INFO-VAX" 12-NOV-1988 08:29
To:	MRGATE::"ARISIA::EVERHART"
Subj:	Re: Reading files opened for batch logs


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Date: 10 Nov 88 18:38:00 GMT
From: debit.dec.com!mayank@decwrl.dec.com  (The fellow who is a good sport has to lose to prove it.)
Organization: Digital Equipment Corporation
Subject: Re: Reading files opened for batch logs
Message-Id: <8811101548.AA00684@decwrl.dec.com>
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To: info-vax@kl.sri.com


 
> I've got a C program that I need to modify to read a file that's already
> open ...  What's the magic stuff to put in  the FAB so I can read it?
> 
> Peter Scott (pjs%grouch@jpl-mil.jpl.nasa.gov)

Peter,

What you essentially want to tell RMS is that you will share the file for read
with any other process that may be writing to it (in any shape or form ;-) ).

Here's what you are looking for :


    x.fab$b_fac = FAB$M_BIO | FAB$M_GET ;
    x.fab$b_shr = FAB$M_SHRGET | FAB$M_SHRPUT | FAB$M_SHRDEL | FAB$M_SHRUPD
    		   | FAB$M_UPI;

I am using Block I/O, so I needed the FAB$M_BIO.  Also, I am not sure whether
the last  FAB$M_UPI is necessary, but it doesn't hurt to put it in anyway.

enjoy,
- mayank vadodaria		mayank%credit.com@decwrl.dec.com  OR
    				decwrl!credit.dec.com!mayank