Date: Sun, 16 Feb 1997 09:25:31 +0200 (IST)
From: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To: Hasdi Rodzmann Hashim <hasdi AT umich DOT edu>
cc: djgpp AT delorie DOT com
Subject: Re: shared libraries
In-Reply-To: <5e07b6$1r6@lastactionhero.rs.itd.umich.edu>
Message-ID: <Pine.SUN.3.91.970216092222.14977E-100000@is>
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII


On 13 Feb 1997, Hasdi Rodzmann Hashim wrote:

> I think we are forgetting the real advantage of shared libraries. Shared
> libraries can hide the implementation details of the operating system.
> That way, if DOS maintainers decide screen printing should be done
> directly instead of using INT 21h-09h, my application doesn't have to
> change, only the libraries. This level of abstraction makes is possible
> for an application to be more portable from one DOS implementation to
> another; Heck, this would work even for different hardware implementation
> (one day it will be i/o port 03E8h, tommorow 040Eh) and application NEVER
> needs to change.

This is, IMHO, too simplistic.  In my experience, the OS-dependent stuff 
is deeply intertwined with the startup code, and cannot be easily 
separated to be put in the shared library.  For more details, look at the 
DJGPP startup code and the stub (e.g., some of the brk/sbrk functionality 
is included there).