X-Recipient: archive-cygwin AT delorie DOT com X-Spam-Check-By: sourceware.org Date: Wed, 20 Oct 2010 16:32:54 -0400 From: Christopher Faylor To: cygwin AT cygwin DOT com Subject: Re: Sending signals to a subprocess Message-ID: <20101020203254.GA11903@ednor.casa.cgf.cx> Reply-To: cygwin AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com References: <20101018183438 DOT GA25878 AT ednor DOT casa DOT cgf DOT cx> <4CBCA2A5 DOT 4010601 AT cornell DOT edu> <20101018201805 DOT GA26254 AT ednor DOT casa DOT cgf DOT cx> <4CBD9DF2 DOT 3090804 AT cornell DOT edu> <20101019141557 DOT GA31784 AT ednor DOT casa DOT cgf DOT cx> <4CBE5F53 DOT 30402 AT cornell DOT edu> <4CBED0C3 DOT 6080001 AT cornell DOT edu> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: cygwin-owner AT cygwin DOT com Mail-Followup-To: cygwin AT cygwin DOT com Delivered-To: mailing list cygwin AT cygwin DOT com On Wed, Oct 20, 2010 at 08:25:37PM +0100, Andy Koppe wrote: >On 20 October 2010 13:20, Andy Koppe wrote: >>>Corinna made tcgetpgrp return 0 instead of -1 in some circumstances >>>(see http://www.cygwin.com/ml/cygwin-patches/2009-q4/msg00045.html) >>>because she saw Linux doing that. ??But when I run Corinna's test on >>>my Linux system, I get -1 where she got 0. ??So not all Linuxes agree >>>on what tcgetpgrp should do. >> >>Hmm, Corinna's test calls tcgetpgrp(master) in the parent only before >>the child is forked and after it exited, so it's correct to report that >>there's no foreground process. >> >>I wonder which Linux it was that returned 0 in case of failure. I've >>tried it on a recent Opensuse, an old Redhat with a 2.6.9 kernel, and >>also a Debian with a 2.4 kernel, and got -1 on all of those. > >Actually I'd only tried my test on all three systems, whereas I'd tried >Corinna's only on the old Redhat, where it did print -1 for failure. >On the 2.4 system it can't open /dev/ptmx, whereas on the Opensuse with >2.6.34 I do get the results Corinna reported, including 0 on the master >side of the pty when enquiring from the parent. (Process 0 is the >startup process, so I guess that makes some sense.) > >To bring my ramblings to some sort of conclusion, here's a slightly >amended version of Corinna's test that checks the master side from the >parent process before, *during* and after the child process: FYI, I'm sticking with the test case that I first posted several days ago and which has been cruelly ignored ever since. I've been slowly modifying it for the last several days. I think I'm seeing some pattern to the way Linux handles this and I should be able to make Cygwin work the same way. Just in case it isn't clear, this all has nothing, AFAICT, to do with the fact that Cygwin doesn't implement TIO[CS]PGRP but I have implemented those two ioctl's nonetheless. cgf -- 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