Running one script once

[billthecreator]

what is that function called where you can only run one script once...

im drawing a blank, and i cant find the right keywords to search the forum with....

[Authenticity]

_Singleton()?

[billthecreator]

_Singleton()?

YES!

Thank you

[MilesAhead]

_Singleton()?

I get a baffling error dialog with _Singleton()

I'm trying to use a GUID in my application for unique identifier. I know it works with system mutex because I have components in other languages that have used it for years.

Anyway, it works as expected in this code

; Script Start - Add your code below here
#include <Misc.au3>
Const $ERROR_ALREADY_EXISTS = 183
If _Singleton("{5788CDF6-1E46-41CB-88D1-E27006A8B69A}",1) = 0 Then
    iF @error = $ERROR_ALREADY_EXISTS Then Exit
EndIf

While 1
WEnd

But if I try to use the same code with a different GUID in a real app, launching the second instance gives me an error dialog "-1 variable used without being declared" instead of quitting quietly

Pretty strange. I even move the #include <Misc.au3> and the _Singleton statement way up to the top of the script to avoid interaction with other includes. No joy. Same thing. -1 without being declared yadda yadda

Edit: I figured it out. It was due to OnAutoItExit() accessing variables that were never made because the script quits.

Edited May 26, 2009 by MilesAhead

[Authenticity]

Did you define $ERROR_ALREADY_EXIST in the other script? Try to run it from SciTE and see what crashing the script and where.