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Date: Tue, 12 Jul 2011 08:20:43 -0400
Message-Id: <E1QgbxD-0005c0-Jw@fencepost.gnu.org>
From: Eli Zaretskii <eliz AT gnu DOT org>
To: djgpp AT delorie DOT com
In-reply-to:
	<639f9631-f9d6-42b8-bf70-f943afe5afa8 AT n28g2000vbs DOT googlegroups DOT com>
	(message from Georg on Tue, 12 Jul 2011 04:30:42 -0700 (PDT))
Subject: Re: Pipe()
References: <639f9631-f9d6-42b8-bf70-f943afe5afa8 AT n28g2000vbs DOT googlegroups DOT com>
Reply-To: djgpp AT delorie DOT com

> From: Georg <dosusb AT googlemail DOT com>
> Newsgroups: comp.os.msdos.djgpp
> Date: Tue, 12 Jul 2011 04:30:42 -0700 (PDT)
> 
> I am trying to port a Linux program to DOS using DJGPP. This program
> uses pipe() to spawn another program in a new daemon which listens on
> the tcp/ip socket for commands from the main program.(using the local
> ip address of the PC)
> 
> The pipe() function of GCC/DJGPP tells the main program that the
> daemon has been started OK.

That's not true.  The DJGPP implementation of `pipe' is just this:

  int
  pipe(int _fildes[2])
  {
    errno = EACCES;
    return -1;
  }

So it actually tells the main program that the daemon failed to
start.  Perhaps the main program doesn't bother to check the return
value or errno, but then it's a bug in that program.

> I guess this is caused since both programs are not running at the same
> time when run with DOS.
> 
> Is there a way to get this to run with DJGPP somehow?

`pipe' is a function that establishes 2-way communications between 2
programs running simultaneously on the same machine.  DOS does not
support such multi-programming, so `pipe' cannot work on DOS.

So there's no easy way of getting that Linux program ported to DJGPP.
You could try converting the daemon into a TSR, but that's hardly a
simple project.

Sorry.