Failed global variable update?

[michele.santucci]

Hallo,

I think I'm having a problem with global variables.

I have a big number of global variables defined into parameters.vi.

Among these parameters I have BOARDS_PATH, this variable is the folder where I have to look for some xml files.

BOARDS_PATH value is changed by Load_Config.vi that reads values from .ini file and set BOARDS_PATH variable

(among the others).

BOARDS_PATH is used by Get_Boards.vi to create an array (Boards) of values I will use to look for specific board profile.

This's the main vi section where Load_Config and Get_Boards are called.

Load_Config.vi do something like this, the stacked sequence is repeated for each possibile entry in the .ini

file (there's a better solution?).

If I debug the main vi global values are correctly set BOARDS_PATH is consistent.

If I run the main vi without debugging it or if I compile it and run the binary then BOARDS_PATH is left at the default value (without any visible error).

[michele.santucci]

BTW the ini file is something like this:

[general]
ProjectPath = "C:\Program Files (x86)\IDS\MAN_TEST_UI"
ReportTemplatePath = "C:\Program Files (x86)\IDS\MAN_TEST_UI\data\report_templates"
BoardsPath = "C:\Program Files (x86)\IDS\MAN_TEST_UI\data\boards"

[MAN_PAIPL]
SACableAtt = 0

[GPIB]
GPIB_E3649A = 10

[Yamaeda]

Welcome to Race Conditions.

In this case, the easy solution is to send out the path as an indicator and wire it directly to the next function.

[michele.santucci]

I got this but it's a workaround that could work for this case only.

I have something like 100 initialization parameters loaded from .ini files to manage and I cannot think to use this approach each time.

[michele.santucci]

how can this code being subject to a Race condition?

Load Config and Get Boards are run sequentially .. if they are not how can Error in -> Error out be kept consistent?

[billko]

How old is this code?  The SSS should be beyond your reach.

[drjdpowell]

You need to execute your load config before reading any of the Global Variables.  In your screenshot, you have written code to read the global variable first.  Put a sequence structure around the Read, with an input error wire to enforce the execution order.   Remember, LabVIEW code does not necessarily execute left to right.

[Yamaeda]

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@michele.santucci wrote:

how can this code being subject to a Race condition?

Load Config and Get Boards are run sequentially .. if they are not how can Error in -> Error out be kept consistent?

---

The Global is read before it's written since you have nothing that forces order.

[michele.santucci · Accepted solution]

I know it's ugly but this way it will work:

[Yamaeda]

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@michele.santucci wrote:

I know it's ugly but this way it will work:

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Yes, that forces order. But it'd be easier to just wire it from the previous VI. 🙂