How to prevent two scripts from running concurrently?

[Rich S]

Hi, all!

In the current solution I'm working on there are multiple buttons for users to select which scripts they'd like to run. The problem is, how do I prevent a second script from running while the first one is running?

I searched the archives here and found 2001 post where a virtual latch was used so whenever a script begins to run, it causes a control field to turn to "1"; when finished with the script it turns that field back to "0". (In the beginning of each script there's a command to check the control field; if it's "1", the second script is terminate using a halt command, if "0" it proceeds.)

I tried using the aforementioned script technique and it still doesn't quite work as I thought it would: the first script "hangs" after the second script bails out.

Suggestions for a tweak, or a different approach to this problem, would be greatly appreciated!

As always, TIAFYT.

Cheers,

Rich

[comment]

The situation is not quite clear. I believe that scripts are queued, so a second script wouldn't run until the first one has finished or paused - whether you do something about it or not.

I am also not sure what you mean by "the first script "hangs" after the second script bails out". If the second script executes a Halt Script[] step, I believe ALL scripts will terminate immediately.

[_henry_]

I agreed with Comment. Usually, if the second script continued, the problem would be not the function of Halt [], but Exit[] script. So, it will only exit the current script. However, if you have multi sub-script, it will be better to use Halt [] to break all script at once...

[Rich S]

(Sorry for the delay in responding to your notes, guys--I work two full-time jobs to make ends meet so sometimes I can't reply as quickly as I'd like to.)

When I said that the first script hangs, I meant that it just stops mid-execution and doesn't continue after it's suddenly interrupted by the offending script. What I'd like to happen is that if the first script is running, and a user accidentally clicks on another button, the second script would be automatically terminated and the first script would continue to run.

Maybe it's the command structure I'm using: the "halt" script is as follows:

Allow user abort [off]

If [Main::Script_Go_NoGo = "1"]

Halt Script

Else

Set Field [Main::Script_Go_NoGo = "1"]

End If

...and the last line of each script is:

Set Field [Main::Script_Go_NoGo = "0"]

So, in theory anyway, once the second script "sees" the flag is set to 1 then it should terminate...but then again, I probably goofed-up in the coding...again. *heavy sigh*

[Lee Smith]

Have you used the tool [color:blue]Script Debugger?

Why not attach a copy of your file (minus any confidential data)?

Lee

[Fenton]

WF7A, you can use Exit Script (exits current script) instead of Halt Script (halts all scripts). Exit script also has an option to return a Result; though I've found it is a bit unreliable unless I initiated it when I didn't want to pass a result.

Example:

If [ Get (LastError) ≠ 0 ]

Exit Script ( "Error" )

Else

Exit Script ("")

End If

Worked. If I left out the Exit Script (""), then sometimes "Error" would show up anyway in the calling script when there was no error. I watched it in Data Viewer. Anyone else see this, or, preferrably, not see this?