Date:	Mon, 27 Jul 1998 18:15:26 +0300 (IDT)
From:	Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
To:	"Salvador Eduardo Tropea (SET)" <salvador AT inti DOT gov DOT ar>
cc:	DJ Delorie <dj AT delorie DOT com>, djgpp-workers AT delorie DOT com
Subject:	Re: Pipes
In-Reply-To:	<m0z0nxd-000S5dC@inti.gov.ar>
Message-ID:	<Pine.SUN.3.91.980727180912.1183F-100000@is>
MIME-Version:	1.0

On Mon, 27 Jul 1998, Salvador Eduardo Tropea (SET) wrote:

> DJ Delorie <dj AT delorie DOT com> wrote:
>  
> > * gdb traps the program exit.  Do the same thing as it does.
> > 
> > * In fact, gdb traps int 0x31.  Maybe your shell could somehow trap
> >   that *before* it gets to the DPMI server, so that longjump is still an
> >   option?
> 
> Hmmm.... but I want a djgpp shell because in this way we can try to add it to 
> bash.

I understand that DJ suggested to use these techniques in the shell you 
are writing.

> > * Why not add a FSEXT that implements named pipes via your shell?
> 
> Don't know what's it. Please explain me a little.

FSEXT is the Filesystem Extensions feature which is built into the libc.  
It allows you to install hooks for specific handles and monitor low-level 
functions called by the library.  For example, you can arrange for your 
function to be called when the library calls _write on handle 2.  Your 
function can then either handle the call and return zero, or return 
non-zero, and libc will then do its usual thing (i.e. call DOS via 
__dpmi_int).

It's a great feature.  More info about it is available in the libc docs 
(look for "File System Extensions").

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