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From: thorinn@diku.dk (Lars Henrik Mathiesen)
Newsgroups: comp.unix.programmer
Subject: Re: shared libraries, when to use them
Keywords: shared libraries .so
Message-ID: <1991Jun21.145445.21905@odin.diku.dk>
Date: 21 Jun 91 14:54:45 GMT
References: <1991Jun11.163544.20234@aio.jsc.nasa.gov> <1991Jun18.050150.17149@thunder.mcrcim.mcgill.edu> <8448@auspex.auspex.com>
Sender: thorinn@skinfaxe.diku.dk
Organization: Department of Computer Science, U of Copenhagen
Lines: 23

guy@auspex.auspex.com (Guy Harris) writes:
> >You can't, because SunOS doesn't have shared libraries.  (What it does
> >have is shared object files.  What's the difference?  You can link in
> >part of a library without linking in the rest, among other things.)

>Just out of curiosity, who *has* implemented shared libraries?

I think Borroughs did on their Bx700 series. If I remember correctly
what I was told, each procedure (and array, ...) resides in its own
segment and is referenced through a descriptor; if it's not in core,
the descriptor ``contains'' a filename and other info.

Whne the Binder on those systems resolve a function name it just
insert the proper descriptor in a global list. When a new library is
installed programs must be rebound, but it is a very quick process;
and since the user code is linked the same way, it is very quick to
make a program use an updated version of a single procedure.

(And if it doesn't work that way, it could've.)

--
Lars Mathiesen, DIKU, U of Copenhagen, Denmark	     [uunet!]mcsun!diku!thorinn
Warning: This article may contain unmarked humour.		thorinn@diku.dk