Path: utzoo!news-server.csri.toronto.edu!rutgers!dimacs.rutgers.edu!seismo!uunet!auspex!guy
From: guy@auspex.auspex.com (Guy Harris)
Newsgroups: comp.unix.internals
Subject: Re: what is in sysV v4?
Message-ID: <6600@auspex.auspex.com>
Date: 13 Mar 91 18:26:01 GMT
References: <27919@netcom.COM>
Organization: Auspex Systems, Santa Clara
Lines: 23

>does anyone know what the fnew features of at&t's sys V version 4 of
>unix? I have herd rummors that is supposed to support dynamic linking.

It does.

>does anyone know how this will work.

The same way it works in SunOS 4.1, essentially (although it doesn't
seem to have the same major/minor version number mechanism that SunOS
4.x does).

>I currently work on a SUN workstation using sunos 4.1. it supports
>"dynamic linking" but I would argue that this is not true dynamic
>linking as it only accures when my program loads. I would link to
>be able to link and load on the fly

Then use "dlopen()" and "dlsym()", which are in both SunOS 4.1 and
System V Release 4.  "dlopen()" takes a pathname of a shareable object
(and a flag argument), maps the shareable object into the process's
address space, and returns an opaque handle for that object.  "dlsym()"
takes a handle for a loaded object, and a pointer to a string containing
the name of a function in that object, and returns a pointer to the
function in question.