Date: Tue, 3 Feb 1998 14:25:44 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: "Salvador Eduardo Tropea (SET)" <salvador AT inti DOT gov DOT ar>
cc: djgpp-workers AT delorie DOT com
Subject: Re: fopen and shared files question
In-Reply-To: <m0xzbYF-000S2dC@inti.gov.ar>
Message-ID: <Pine.SUN.3.91.980203141432.22546B-100000@is>
MIME-Version: 1.0
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On Tue, 3 Feb 1998, Salvador Eduardo Tropea (SET) wrote:

> > So what is different about your editor that you cannot?
> The OS that we used.

Sorry, I missed the fact that you were using Windows 3.X.

> > Can you post a simple test program that fails when run on the same
> > file in two different DOS boxes?
> Any will do it.

So on Windows 3.X you cannot browse the same file from two different DOS 
boxes using the DJGPP port of Less?  (I'm sorry I cannot test this easily 
myself, since I almost never install SHARE, so I cannot find a DOS 
machine with it installed nearby.)

> Win3.11 (No WfW) + Win32s:

3.11 or 3.1?  AFAIK, 3.11 and WfW is the same, no?

Also, did you enable 32-bit file access mode?  (If you did, I think 
Windows uses its VSHARE.386 driver instead of SHARE.)

> SHARE is very important here.

This is so strange!...  First, I would expect SHARE to behave the same as
(or close to) Windows 95's built-in VSHARE driver.  And second, did you 
use DOS SHARE.EXE or Windows VSHARE.386?

> With SHARE loaded the share flags are very important.

Does the behavior contradict the table in the Interrupt List?

> The solution (if it exists) will set the share flags according to
> the read & write status.

If we can come up with a set of tests which will work in most of the 
cases, I personally don't see anything wrong with looking at Windows 
version to decide what to do.

> My idea is to emulate the W95 
> logic under W3.11 because W95 uses a very good policy.

I agree.