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From: Charles Sandmann <sandmann AT clio DOT rice DOT edu>
Newsgroups: comp.os.msdos.djgpp
Subject: Re: spawning djgpp programs...
Date: Tue, 28 Nov 1995 15:50:45 CST
Organization: Rice University, Houston, Texas
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References: <48v6af$moq AT news DOT cea DOT fr>
Reply-To: sandmann AT clio DOT rice DOT edu
Nntp-Posting-Host: clio.rice.edu
To: djgpp AT sun DOT soe DOT clarkson DOT edu
Dj-Gateway: from newsgroup comp.os.msdos.djgpp

> What is the memory management like when you spawn a djgpp program (converted
> to .exe by coff2exe) from a djgpp program ?
> In V1.12, Is go32 repeated twice in memory ? How is the 32bit data segment shared ?

In V1.1x, you get multiple copies of GO32, but the contents of the first image
memory are not accessible at all by the second.

> And in V2 ?

Somewhat depends on the DPMI provider.  DPMI 0.9 providers share IDT and
page tables, so you can access the memory image of the parent from the
child using the farptr functions (selector/address).

> If I give to my second program the address of a function of my first (father) 
> program in parameter, is it possible to make a call from one code segment to
> the other ??

V1.x, absolutely not.  V2.x, you would have some real problems settting
up the calls, since you would have to make a far call/far return, and
set up the DS/SS so that things were consistent.