From: Anonymous <derykus@...>
Date: 2009-05-28T01:45:06+09:00
Subject: Re: Running code at a certain time?

On May 25, 3:40 pm, Tom Ricks <carrottop...@gmail.com> wrote:
> Caleb Clausen wrote:
> > On 5/25/09, Tom Ricks <carrottop...@gmail.com> wrote:
> ...
>
> Well, I'm not really sure. The intent is to have a repetitive code ran
> at quite a few different times with changing variables. The sleep option
> doesn't really seem reliable and realistic, although its the only thing
> so far. The code I can come up with is this:
>
> class TestClass
>   def testtime(timetorun)
>     timetorun = @timetorun
>     sleep(1) while Time.now.strftime("%I:%M:%S %p") < ("#{@timetorun}")
>     #Somewhere code to run when Time.now = timetorun
>   end
> end
> test = TestClass.new
> test.testtime("11:04:40 AM")
>
> The problems are #1. I don't know how to link the time code to the code
> to be run when the time code is fulfilled. #2. If I have a list of times
> to be run, and one time is out of order, it will just sleep past the out
> of order time. #3. While the code is waiting for a certain time, with
> sleep, it cannot do anything else. Is there a way that I can run code
> that will watch for a time to be fulfilled on many levels instead of
> just waiting until a time, moving on and waiting for the next? Is it
> possible to do something like this:
>
> when test.testtime is true/finished?
>  run some code
> end
>
> > In some cases, you might be able
> > to put your sleep and code_to_be_delayed in another thread, but then
> > you run into the problem of thread synchronization.
>
> How would I do this?
>
> Your example of
>
> sleep(target_time-Time.now)
> code_to_be_delayed
>
> seems to work better, although it still shuts the whole code down for a
> while.

I'm totally new to Ruby so I'm sorry for the  piggyback question but,
in Perl you could
set an alarm clock that'd leave the program unfettered:


  { local $SIG{ALRM} = sub { die "timeout" };
    alarm( "target_time" - "Time.now" );
     # do other things
    alarm( 0 );
  };
  if ( $@ =~ /^timeout/ ) {# time's up... }
  elsif ( $@ )            {# other error... }


How would Ruby do this?

Thanks,
--
Charles DeRykus