> From: Junio C Hamano [mailto:gitster@xxxxxxxxx] > Sent: Thursday, August 30, 2012 7:14 PM > To: Joachim Schmitz > Cc: git@xxxxxxxxxxxxxxx > Subject: Re: [PATCH 1/2] Support for setitimer() on platforms lacking it > > "Joachim Schmitz" <jojo@xxxxxxxxxxxxxxxxxx> writes: > > >> I see no existing code calls setitimer() with non-NULL ovalue, and I > >> do not think we would add a new caller that would do so in any time > >> soon, so it may not be a bad idea to drop support of returning the > >> remaining timer altogether from this emulation layer (just like > >> giving anything other than ITIMER_REAL gives us ENOTSUP). That > >> would sidestep the whole "we cannot answer how many milliseconds are > >> still remaining on the timer when using emulation based on alarm()". > > > > Should we leave tv_usec untouched then? That was we round up on > > the next (and subsequent?) round(s). Or just set to ENOTSUP in > > setitimer if ovalue is !NULL? > > I was alluding to the latter. OK, will do that then. > >> > + switch (which) { > >> > + case ITIMER_REAL: > >> > + alarm(value->it_value.tv_sec + > >> > + (value->it_value.tv_usec > 0) ? 1 : 0); > >> > >> Why is this capped to 1 second? Is this because no existing code > >> uses the timer for anything other than 1 second or shorter? If that > >> is the case, that needs at least some documenting (or a possibly > >> support for longer expiration, if it is not too cumbersome to add). > > > > As you mention alarm() has only seconds resolution. It is tv_sec > > plus 1 if there are tv_usecs > 0, it is rounding up, so we don't > > cancel the alarm() if tv_sec is 0 but tv_usec is not. Looks OK to > > me? > > Can a caller use setitimer to be notified in 5 seconds? Yes, by setting tv_sec to 5 and tv_usec to 0, or be setting tv_sec to 4 and tv_usec to something > 0. Unless I screwed up the operator precedence? To make it clearer (any possibly correct?): switch (which) { case ITIMER_REAL: alarm(value->it_value.tv_sec + ((value->it_value.tv_usec > 0) ? 1 : 0)); Or even just switch (which) { case ITIMER_REAL: alarm(value->it_value.tv_sec + (value->it_value.tv_usec > 0)); -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html