While 1 WEnd CPU usage?

[Scoox]

Hi all, since I'm totally new to AutoIT, I guess I'm allowed to ask silly questions. Coming from AutoH*tkey, I thought an effective way to learn AutoIT would be to try and port a few of my own AHK scripts to AutoIT. I'm now looking into how to make scripts "permanent", that is, scripts that continue to run indefinitely until execution is explicitly terminated. From what I've read and seen this is done using something like this:

While 1
WEnd

The above code results in high CPU usage—obviously. Adding a Sleep() to it takes care of the CPU hogging:

While 1
    Sleep(1000)
WEnd

I don't understand, however, why the following code doesn't cause high CPU usage, does execution stop at GuiGetMsg() until something happens on the GUI?:

While 1
    $nMsg = GuiGetMsg()
    ; ... other code ...
WEnd

I just want to know what's considered best practice, thanks!

[Melba23]

Scoox,

GUIGetMsg has its own built-in Sleep of about 15ms (it varies depending on CPU loading) so you do not need a separate command. A Sleep(10) is more than sufficient to keep any other tight loop from frying the CPU - and as any shorter time parameter is automatically extended to 10ms there is no point in going lower, although tests have proved that even few nanoseconds are sufficient to prevent this.

All clear?

M23

[FrancescoDiMuro]

@Scoox
Hi, and welcome to the AutoIt forum
Directly from the Help file about GUIGetMsg():

This function automatically idles the CPU when required so that it can be safely used in tight loops without hogging all the CPU.

 

[Tersion]

Scoox,

Nice question! I'm same new to AutoIt and for a while wondering about this Sleep() tricks in empty While loops.

Melba23 and FrancescoDiMuro,

Thanks for explanations about what going on under the hood!

[Scoox]

@Melba23 thanks for the insightful answer, and @FrancescoDiMuro for reminding me to RTFM