[maemo-developers] sensing change in System Clock using Qt

From: nomrasco nomrasco at gmail.com
Date: Sun Jan 31 14:59:30 EET 2010
ibrahim wrote:
> I am very sorry for not making my question clear enough. But the
> situation you just described is JUST what I want to do! Yes, I want to
> do something exactly as you described; I am now at 4:00 am, I need to
> make my app do something at - say - 8:00 am (the time of the alarm is
> calculated and varies from time to time, so i can't just use cron jobs
> to schedule the next alarm), So, I used a QTimer and set its interval to
> the duration between now and the next alarm. BUT this solution won't
> work if user decides to adjust the system clock/change timezone.
> What I'm asking is there anyway to GET NOTIFIED by the system when > its
> clock/timezone changes (in order to recalculate the next alarm and set
> my Qtimer object to a new duration)?? any signal emitted ? anything?

> I hope i made my question clear and sorry for any inconvenience.
> thanks again


   You should check libalarm API and its feautures (
http://maemo.org/api_refs/5.0/5.0-final/libalarm/). It provides You exactly
what You want... the only problem is that it is in pure C. You can add alarm
and forget about QTimer etc. Device could be even boot up on You alarm if
that is a behaviour You would like to get (and device was switched off
before Your alarm;) ). It should not be to hard to use this library in Qt
code. Furthermore, You can check another library provided by Nokia - libtime
(http://maemo.org/api_refs/5.0/5.0-final/clockd/). It allows You to
communicate with clockd which is responsible for maintaining time on the
device. clockd daemon also sends D-Bus signal (
http://maemo.org/api_refs/5.0/5.0-final/clockd/libtime_8h.html just at the
top of the page :) ) after time was changed by the user or time was
synchronized and changed to different GMT offset (this is not working with
every GSM network though).

   So.. fast reply for Your question is: signal send by clockd. Better
solution: use libalarm which will save You a lot of time :)

Best Regards
software development
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