From:	"Paul Derbyshire" <pderbysh AT usa DOT net>
Newsgroups:	comp.os.msdos.djgpp
References:	<9805190821 DOT AA00045 AT gcef DOT gc DOT maricopa DOT edu>
Subject:	Re: Threading
Lines:	38
Organization:	The Chaos Zone
MIME-Version:	1.0
Message-ID:	<aBg81.1407$qR3.6128286@news20.bellglobal.com>
Date:	Tue, 19 May 1998 14:23:02 GMT
NNTP-Posting-Host:	206.172.228.152
NNTP-Posting-Date:	Tue, 19 May 1998 10:23:02 EDT
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

So a 'fake' SIGSEGV is used?

1. Is there a way to diddle a hardware interrupt(timer) to return to an altered
address
    using assembly under DPMI?
2. Is it possible to make a disk file containing relocatable compiled C++ code
that can
    be dynamically loaded into memory and linked-to? How would one accomplish
    this? The most obvious way would be to package individual
dynamically-loading
    classes that will have a common interface (e.g. plugin architecture), write
an
    "abstract base class" with function pointers that look and act like virtual
function
    members implementing the interface, and load specific plugin classes at
runtime
    into some allocated memory, locate the entry points (their offsets in the
file/data
    presumably have been extracted and recorded in an additional data structure
in the
    files) and put their relocated addresses in the function pointers of an
instance of
    the interface class, and at other offsets in the plugin replace placeholder
    0x00000000's with the addresses of methods it calls from the standard
library (if
    library use is made available to the modules at all, which it should be
ideally).

--
   .*.  "Clouds are not spheres, mountains are not cones, coastlines are not
-()  <  circles, and bark is not smooth, nor does lightning travel in a
   `*'  straight line."    -------------------------------------------------
        -- B. Mandelbrot  |http://www3.sympatico.ca/bob.beland/indexn2f.html
_____________________ ____|________     Paul Derbyshire     pderbysh AT usa DOT net
Programmer & Humanist|ICQ: 10423848|

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