Mailing-List: contact cygwin-developers-help AT sourceware DOT cygnus DOT com; run by ezmlm
List-Subscribe: <mailto:cygwin-developers-subscribe AT sources DOT redhat DOT com>
List-Archive: <http://sources.redhat.com/ml/cygwin-developers/>
List-Post: <mailto:cygwin-developers AT sources DOT redhat DOT com>
List-Help: <mailto:cygwin-developers-help AT sources DOT redhat DOT com>, <http://sources.redhat.com/ml/#faqs>
Sender: cygwin-developers-owner AT sources DOT redhat DOT com
Delivered-To: mailing list cygwin-developers AT sources DOT redhat DOT com
Date: Sun, 25 Mar 2001 19:06:58 +0400
From: Egor Duda <deo AT logos-m DOT ru>
X-Mailer: The Bat! (v1.45) Personal
Reply-To: Egor Duda <cygwin-developers AT cygwin DOT com>
Organization: DEO
X-Priority: 3 (Normal)
Message-ID: <183264218826.20010325190658@logos-m.ru>
To: "Robert Collins" <robert DOT collins AT itdomain DOT com DOT au>
CC: cygwin-developers AT cygwin DOT com
Subject: Re: setup will have to wait :[
In-reply-To: <000501c0b3e9$7fa3d890$0200a8c0@lifelesswks>
References: <001b01c0b397$2d1ca720$0200a8c0 AT lifelesswks>
 <1783665564 DOT 20010323155742 AT logos-m DOT ru>
 <000501c0b3e9$7fa3d890$0200a8c0 AT lifelesswks>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit

Hi!

Saturday, 24 March, 2001 Robert Collins robert DOT collins AT itdomain DOT com DOT au wrote:

>> RC> For data transfer, I was thinking of using shared named
RC> memory:anyone
>> RC> know of caveats for that on win9x?
>>
>> 1. it won't work with non-cygwin apps.
>> 2. the biggest problem with fifo is that there can be several readers
>> and several writers. and i don't know how to implement the following
>> thing: when all writers die all readers should receive eof. and it
>> should work even if writers haven't had a chance to exit gracefully,
>> but was killed from taskmanager, for example. Similarly, when all
>> readers die, writers should unblock with EPIPE.

RC> 1. Do "non-unix" apps understand the concept of a FIFO file?

directly -- not, but they can possibly inherit, say, stdout handle
from parent cygwin process, and it can possibly be a handle of fifo.
For example, you run
"sh -c ./some-script.sh >fifo-to-script-log-processor"
and 'some-script.sh' contains non-cygwin apps

RC> I know that cygwin already has named pipe support

? what do you mean by this? do you mean native calls such as
CreateNamedPipe () etc. or something else?

RC> so is there any reason to try and make FIFO support interoperate
RC> (and what should it appear as?) 

RC> 2. Do you have a reference? So far I've found lots of sys/stat.h header
RC> files :].  If you don't are writes and reads atomic?

no, at least i don't think that they must be.

RC>  Do all readers recieve all the same data from each writer -

no, every byte written to fifo is read by only one reader, though it
can be anyone of them.

RC> or do they pair off? (That sounds rather dirty I know :])

i generally use linux and freebsd as reference. just logon to the
nearest linux box and try :) i've also found it quite helpful to look
into linux and/or bsd kernel sources to understand how things work.

Egor.            mailto:deo AT logos-m DOT ru ICQ 5165414 FidoNet 2:5020/496.19