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Re: delay function
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Re: delay function


  • Subject: Re: delay function
  • From: Brendan Younger <email@hidden>
  • Date: Tue, 07 Dec 2004 22:29:45 -0600


On Dec 7, 2004, at 9:25 PM, Ricky Sharp wrote:


On Dec 7, 2004, at 9:18 PM, Thomas Davie wrote:
On 8 Dec 2004, at 02:43, Ricky Sharp wrote:


I current have it set to 50 ms which would be just over 6 ticks. I have yet to fine-tune this. At 8-ticks it seems a bit too high when comparing it to what the built-in widgets do (e.g. NSButton).

A quick note - you're much better off using an NSTimer to fire an event when you need to unhighlight your control – that way only the threads that depend on that control block and the rest of your computation continues – much better for multitasking.

That's a good tip. I'll definitely revisit this code later to ensure it's a good citizen. I will especially need it in an upcoming title which will be using threads to run the AI portion of a game.

While I would agree that a timer is much better general practice for this sort of thing, you need to remember that NSRunLoop is not exactly fit for real-time processing. In fact, NSRunLoop will often "cheat" with timer fire dates and fire just a little early to make sure that your callback will be called in time. For a UI element, you most certainly do not want the highlight delay to be variable, which it certainly will if you use NSTimers. Using +[NSThread sleepUntilDate:] is the correct call in this case since it will NOT block other threads, even though sleep() and usleep() might. In fact, +[NSTimer sleepUntilDate:] actually calls the Mach function thread_switch() underneath (curse pthreads for not having a pthread_sleep() function!). If you're curious, add a breakpoint on _NSMilliSleep() (I'm pretty sure that's the correct name) which you can see in the disassembly just calls thread_switch(). One final thing to note is that Mach does not promise that it will be able to sleep a thread for any amount of time; it may well be that every other thread in the system is blocked on some resource, but I've yet to actually see this in practice.


Brendan Younger

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  • Follow-Ups:
    • Re: delay function
      • From: Thomas Davie <email@hidden>
References: 
 >Re: delay function (From: Gregory Weston <email@hidden>)
 >Re: delay function (From: Ricky Sharp <email@hidden>)
 >Re: delay function (From: Gregory Weston <email@hidden>)
 >Re: delay function (From: Ricky Sharp <email@hidden>)
 >Re: delay function (From: Thomas Davie <email@hidden>)
 >Re: delay function (From: Ricky Sharp <email@hidden>)

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