AutoHotkey Community

[Peter]

In AHK v1.0.46.01+, Gui can use static variables, but GuiControl doesn't seem to work then. (Tested on AHK v1.0.46.07 and v1.0.46.14)
Maybe it's meant to be like that, but I can't find it mentioned in AHK Help.

[Chris]

The problem also extends to ByRef variables. It will be fixed in the next release and the changelog will say: Fixed GuiControl, GuiControlGet, and "Gui ListView/TreeView" to support static variables and ByRef's that point to globals/statics.

Thanks for reporting it.

[Peter]

The previous bug is solved, but I'm not sure about the behaviour under a label in Function.
GuiControl under the label doesn't work.
Is this a known limitation or some bug as well? (Tested in AHK V1.0.47.00)

[PhiLho]

SetTimer doesn't work well in functions, because the function was exited when the timer goes off, so context (local variables) is lost.
I believe this has been discussed before, so I searched. I found at least two related topics, started by yourself!
Array%index% doesn't work in label inside a function
Crash with SysGet in label inside function
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vPhiLho := RegExReplace("Philippe Lhoste", "^(\w{3})\w*\s+\b(\w{3})\w*$", "$1$2")

[Peter]

[Chris]

This behavior is unexpected; but it turns out there's two reasons for it:
1) The current architecture has no means of supporting static variables for GUI controls unless the function was actually called (not entered via a subroutine like SetTimer).
2) Performance: Keeping this limitation speeds up GUI variables when they're looked up outside of a function.

Due to obscurity, I really don't want this in the documentation. I checked both spots where it could be mentioned, but it would really make a mess of the already-complicated wording.

[corrupt]

[Chris]

Supporting timers and other externally-called subroutines inside functions was never intended. At the time it was discovered, I was tempted to disable it but decided to keep it because some people said they were using it. Unfortunately, that feature is limited; certain types of extensions (like the one in this topic) can't be added to it without redesigning certain key data structures, which would increase memory load across-the-board (even in scripts that don't use the feature).

[corrupt]

Understood, but intentionally leaving gotcha information out of the documentation seems unprofessional IMHO... Maybe users here should start a new manual that contains an alphabetical list of gotchas and things that you don't want to add to the documentation?

[Chris]

By all means. My rule-of-thumb is that if 99.9% of readers would want their time back after reading something, including it would do more harm than good.

[engunneer]

corrupt,

You should start a additional documentation page on the official wiki. Title it Gotchas if you want, but I think a better name would be, well, better.
_________________
Unless otherwise noted, all code is untested.
Common Answers: 1.(Loops, Viruses, etc.) 2. Search 3.RTFM

[Peter]

[Chris]

This situation isn't exceptional merely because of the rarity of using static variables for GUI controls. It's exceptional because the problem doesn't occur unless the GUI control labels (or timers) are also inside a function. So if you want to use static variables for GUI controls -- and those controls need timers or GUI event-driven subroutines -- you should put those subroutines outside of the function and have them call the function in a special mode (e.g. by passing a special value via parameter). This is because calling a function is the only way that the program is designed to allow access to static variables dynamically (which includes GUI variables because they are looked up dynamically).

I don't wish to mention this on the GUI page because it's already so long that most readers give up long before reaching the end. However, I've revised the wording on the Functions page to mention it:

[Peter]

[Chris]

Thanks for the example and the comments it contains.