delorie.com/archives/browse.cgi | search |
X-Recipient: | archive-cygwin AT delorie DOT com |
X-SWARE-Spam-Status: | No, hits=-3.5 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_LOW,SPF_HELO_PASS,SPF_PASS |
X-Spam-Check-By: | sourceware.org |
To: | cygwin AT cygwin DOT com |
From: | Eric Blake <ebb9 AT byu DOT net> |
Subject: | bi-directional named pipe |
Date: | Thu, 2 Jul 2009 14:55:16 +0000 (UTC) |
Lines: | 51 |
Message-ID: | <loom.20090702T144136-702@post.gmane.org> |
Mime-Version: | 1.0 |
User-Agent: | Loom/3.14 (http://gmane.org/) |
X-IsSubscribed: | yes |
Mailing-List: | contact cygwin-help AT cygwin DOT com; run by ezmlm |
List-Id: | <cygwin.cygwin.com> |
List-Subscribe: | <mailto:cygwin-subscribe AT cygwin DOT com> |
List-Archive: | <http://sourceware.org/ml/cygwin/> |
List-Post: | <mailto:cygwin AT cygwin DOT com> |
List-Help: | <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs> |
Sender: | cygwin-owner AT cygwin DOT com |
Mail-Followup-To: | cygwin AT cygwin DOT com |
Delivered-To: | mailing list cygwin AT cygwin DOT com |
The upcoming upstream Autoconf 2.64 release will introduce a new feature for parallel testsuite execution, which can vastly decrease the time spent testing several packages (autoconf itself, m4, tar, findutils, ...). However, it currently requires support for bi-directional named pipes. POSIX does not require this, but Linux provides it; is there any chance of implementing it in cygwin? On Linux: % mkfifo fifo % exec 5<>fifo % echo hi >&5 % read a <&5 % exec 5<&- % echo $a hi % rm fifo % On Cygwin: $ mkfifo fifo $ exec 5<>fifo $ echo hi >&5 bash: echo: write error: Communication error on send $ echo $? 1 $ read a <&5 $ echo $? 1 $ exec 5<&- $ echo $a $ rm fifo $ In isolation, I can work around this with two fd's, but the autoconf usage is more involved, so I'm not sure if using two fd's instead of a single read-write fd will introduce other problems. $ exec 5<fifo 6>fifo $ echo hi >&6 & $ read a <&5 $ wait $! $ exec 5<&- 6>&- $ echo $a hi $ rm fifo $ -- Eric Blake -- Problem reports: http://cygwin.com/problems.html FAQ: http://cygwin.com/faq/ Documentation: http://cygwin.com/docs.html Unsubscribe info: http://cygwin.com/ml/#unsubscribe-simple
webmaster | delorie software privacy |
Copyright © 2019 by DJ Delorie | Updated Jul 2019 |