X-Recipient:	archive-cygwin AT delorie DOT com
DomainKey-Signature:	a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:date:message-id:from:reply-to:to:subject
	:references:in-reply-to:content-type; q=dns; s=default; b=XA/RQS
	Yhy6ycUa9cSfD5VNeCk5ZWiE7Qyzr3hr6GYJpY+byhzXCDCFJ5UfMpwAsInlugmM
	guaxd+7aNHtFWYfcBACu4zufUU+aO4+kFip1Zln4o5uUBPGDfYflt+G4cQIjcVRg
	HXUW8DIsoeWwSr1TSNUD2WoetoIsXjw7nLWWM=
DKIM-Signature:	v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:date:message-id:from:reply-to:to:subject
	:references:in-reply-to:content-type; s=default; bh=/gNlwrxlnGws
	ax1hu9+FfB2CN30=; b=sufFlSfIhpe8NSH4c5OBz+pTJkiWSCNFh7XXZK8Jj3gH
	xbR/0bzmqMrP96xli7o9It1Nc09hNtVX2Nq7GQ8lj+wAqCX89KWgPQ9tnajrNO4e
	9TMpBrGYPSSKv0RzizxfbgFvrzJcLpWrrLLueNy9Hz3yskAuYv3f0LBAzXE34wk=
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
Authentication-Results:	sourceware.org; auth=none
X-Spam-SWARE-Status:	No, score=-2.3 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_LOW,SPF_PASS autolearn=ham version=3.3.1 spammy=executive, accuracy, traditional, interest
X-HELO:	lb2-smtp-cloud9.xs4all.net
Date:	Sun, 14 Jul 2019 15:19:17 +0200
Message-ID:	<2f15106bf3becd524ac77e7bf0209d31@smtp-cloud9.xs4all.net>
From:	Houder <houder AT xs4all DOT nl>
Reply-To:	cygwin AT cygwin DOT com
To:	cygwin AT cygwin DOT com
Subject:	Re: sigpending() incorrectly returns signals pending on other threads
References:	<CAJouXQne09R+j+k+ZNw5fsZTFqDG5_9iwm9KQnxHoycL+ap_KQ AT mail DOT gmail DOT com> <CAJouXQksOsqWV=pVAJrXPn2FKtAyUO3QTxpugJ9R9rLGEN91UQ AT mail DOT gmail DOT com> <20190712153351 DOT GH3772 AT calimero DOT vinschen DOT de>
In-Reply-to:	<20190712153351.GH3772@calimero.vinschen.de>
User-Agent:	mua.awk 0.99

On Fri, 12 Jul 2019 17:33:51, Corinna Vinschen  wrote:

> On Jul  6 19:15, Kenton Varda wrote:

> > I found a second problem which may or may not be related:

> > If two threads use pthread_kill() to send each other the same signal,
> > such that the signal should be separately pending on both threads at
> > the same time, only one of the two signals is actually queued. It
> > seems that pthread_kill() is ignored if the same signal is already
> > pending on some other thread.
> 
> The current signal mechanism in Cygwin only allows for a signal to be
> queued once.  Changing that is a pretty ambitioned task, which I simply
> don't have enought time for.  However, patches to change that are more
> than welcome.

.. uhm, just a note in the interest of accuracy ...

 - standard signals (which include USRSIG1 and USRSIG2) are not queued
   (traditional signal semantics)
 - only real-time signals should be queued ...

The executive (cygwin1.dll) must maintain a record of the signals that
are pending for the process as a whole,
 as well as a record of the signals that are pending for each thread.

A call to sigpending() returns the union of the set of signals that are
pending for the process
 and those that are pending for the calling thread.

Source: 33.2.1 (How the Unix Signal Model maps to threads) of LPI.

Undoubtedly, the signal mechanism in Cygwin must be "adapted", but
as far as I can tell, there is no requirement to "queue" any of the
standard signals ...

Regards
Henri


--
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

- Raw text -