X-Recipient: archive-cygwin AT delorie DOT com X-SWARE-Spam-Status: No, hits=-0.6 required=5.0 tests=AWL,BAYES_00,SPF_NEUTRAL,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Message-ID: <4CC39F3A.8040808@cornell.edu> Date: Sat, 23 Oct 2010 22:51:38 -0400 From: Ken Brown User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9.2.9) Gecko/20100915 Thunderbird/3.1.4 MIME-Version: 1.0 To: cygwin AT cygwin DOT com Subject: Re: Sending signals to a subprocess 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> <20101020203254 DOT GA11903 AT ednor DOT casa DOT cgf DOT cx> In-Reply-To: <20101020203254.GA11903@ednor.casa.cgf.cx> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm List-Id: 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 10/20/2010 4:32 PM, Christopher Faylor wrote: > 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. This seems to be fixed in the latest snapshot, as far as emacs is concerned. I no longer see any difference between Cygwin and Linux there. I also get the expected results when I run the test cases that Andy posted. But when I run the original test case that you posted in http://cygwin.com/ml/cygwin/2010-10/msg00395.html I'm getting strange behavior. I ran it with no argument, getting 0 = tcgetpgrp(4) 0 = ioctl(fd, TIOCGPGRP, &pid), pid = 0 but then the terminal seemed to hang, and I didn't get a new prompt. I tried this both in mintty and xterm. Ken -- 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