bug#5822: run-at-time and Setting system time

[chandan <chandan.babu@globaledgesoft.com>]

Eli Zaretskii wrote:
>> Date: Fri, 02 Apr 2010 12:29:42 +0530
>> From: chandan <chandan.babu@globaledgesoft.com>
>> Cc: 
>>
>> (defun mwnn-timer-callback ()
>>   (message "Hi, inside mwnn-timer-callback"))
>>
>> (run-at-time "60" nil 'mwnn-timer-callback)
>>
>> The above code is supposed to cause mwnn-timer-callback to get invoked 
>> after 60 seconds. But if the system time is changed to a future date 
>> (say 20 seconds after the timer is started) the timer fires immediately.
>>
>> Is this is a bug in the emacs code. If yes, can this be rectified?
>>     
>
> I think this how the timers are supposed to behave.  They are not
> interval timers, if that's what you expected.
>
>   
Emacs seems to use setitimer & getitimer (interval timers) for 
implementing the timer module. This may be the cause of the problem. 
Using timer_create, timer_delete, timer_settime, timer_gettime etc.