Re: [PATCH] git daemon: avoid calling syslog() from a signal handler

From: Junio C Hamano <gitster@pobox.com>
Date: Jul 5, 2008, 17:26 UTC
Message-ID: <7vabgwtf6m.fsf@gitster.siamese.dyndns.org>
In-Reply-To: <alpine.DEB.1.00.0807051201320.3334@eeepc-johanness>

Johannes Schindelin <Johannes.Schindelin@gmx.de> writes:

Show 6 quoted lines

>> So you will check every 1ms to see if there are new dead children, but why
>> is this necessary?
>
> This comes from me not reading the man page for poll() properly.  Of 
> course, I want to check every second: syslog timestamps the messages with 
> a resolution of 1 second, AFAIR, or at least some of them do.

Hmm.

The question was not about the millisecond typo, but about why time-out at all.

We would need to somehow break out of poll() after handling the SIGCHLD signal and I guess timing the syscall out would be the most obvious way, but somehow it felt awkward.

Another way would be to set up a pipe to ourself that is included in the poll() and write a byte to the pipe from the signal handler.