From debbugs-submit-bounces@debbugs.gnu.org Mon May 25 04:02:13 2020 Received: (at 41507) by debbugs.gnu.org; 25 May 2020 08:02:13 +0000 Received: from localhost ([127.0.0.1]:39722 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jd83p-0004En-0m for submit@debbugs.gnu.org; Mon, 25 May 2020 04:02:13 -0400 Received: from mail1.fsfe.org ([217.69.89.151]:42114) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1jd83m-0004BX-H3 for 41507@debbugs.gnu.org; Mon, 25 May 2020 04:02:11 -0400 From: Jelle Licht To: Ludovic =?utf-8?Q?Court=C3=A8s?= Subject: Re: [bug#41507] [PATCH Shepherd 0/2] Use 'signalfd' on GNU/Linux In-Reply-To: <87tv04wjm9.fsf@gnu.org> References: <20200524142700.6151-1-ludo@gnu.org> <87o8qd2wos.fsf@jlicht.xyz> <87tv04wjm9.fsf@gnu.org> Date: Mon, 25 May 2020 10:02:07 +0200 Message-ID: <87mu5wv3wg.fsf@jlicht.xyz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 41507 Cc: 41507@debbugs.gnu.org X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: debbugs-submit-bounces@debbugs.gnu.org Sender: "Debbugs-submit" X-Spam-Score: -3.3 (---) Ludovic Court=C3=A8s writes: >> As I read it, you need to set up a signalfd handlers for specific >> signals before ever calling `sigaction'. Does this not have an impact on >> being able to do some forms of REPL-driven development with shepherd? > > It depends, I don=E2=80=99t test things like SIGCHLD handling from the RE= PL > anyway. :-) > >> Perhaps it makes sense to document this gotcha (and some of its >> implications) in a location other than an inline comment in >> `maybe-signal-port'. > > Where would you document that? Currently, one gets a warning if signals > cannot be properly blocked. Being able to use both sigaction-based handlers and signalfd is simply weird, not forbidden. When I read=20 --8<---------------cut here---------------start------------->8--- "already X>1 threads running, disabling 'signalfd' support" --8<---------------cut here---------------end--------------->8--- I would already have to understand why this is ("I didn't start any threads, what is going on"). Your inline comment clearly indicates some possible approaches to debug this warning. Knowing that I should call this before any sigaction stuff seems relevant enough to be documented. The Texinfo manual could have a (tiny) section on this. The _only_ way to learn this is by already being a Guile-guru, or by reading the source. - Jelle