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Date: 23 May 2004 08:08:22 +0200
Message-Id: <uwu33ad61.fsf@gnu.org>
From: Eli Zaretskii <eliz AT gnu DOT org>
To: djgpp AT delorie DOT com
In-reply-to: <4d201f78.0405210913.26a5ffcb@posting.google.com>
	(048321887-0001 AT t-online DOT de)
Subject: Re: Using DR-DOS fork in DJGPP
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> From: 048321887-0001 AT t-online DOT de (Udo Kuhnt)
> Newsgroups: comp.os.msdos.djgpp
> Date: 21 May 2004 10:13:22 -0700
> 
> Well, I do not know anything about the start command you mentioned

On a Windows machine, type "start /?" from the DOS box's prompt, and
read there.

> but I thought that if Z_Dom_Fork makes an exact copy of the first 4
> MB of the address room, then it would also copy the file handles.

No, copying the process's address space is not enough.  File handles
are indices into the OS data structure; to copy a file handle, you
need an equivalent of the `dup' system call (DOS function 45h),
otherwise handle inheritance will not work.

> > It would be interesting to see what happens with this aspect of the
> > process created by X_PCreate.
> 
> Since the child and parent process share the same VM, the file handles would
> probably be the same for both processes.

??? Are you saying that all the programs that run in the same VM have
identical handles?  That's simply not true.

> If this succeeds, the X_PCreate function could be used to fork a new process
> in DJGPP, right?

I think it's easier to simply ask Caldera about this.