erro in help for LV 2009- For Loops and While Loops

[Ben]

I found this

That will leak memory as well.

Open once before and close after.

Ben

[Cory_K]

Is that an error? That seems like it would be expected, each Open Reference should allocate memory.

Probably bad coding practice, but expected results I guess.

[Ben]

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Cory K wrote:

Is that an error? That seems like it would be expected, each Open Reference should allocate memory.

Probably bad coding practice, but expected results I guess.

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I believe the documentaion is in error if THAT is the THAT you were refering to.

Opens should be performed as infrequently as possible.

Ben

[Cory_K]

Ahh, so you are saying that they shouldnt even suggest opening a reference within a loop?

[Ben]

If absolutely required well then you have no choice. Every open allocates memory.

To prove to yourself...

Before you go home on Friday afternoon write a VI that repeatedly opens a closes a VISA ref in a While loop with no delays.

Note the amount of memory used when you start the app then let it run over the week-end.

Monday morning your will find more memory being used than Friday.

Stop the app and exit LV and watch the effects on the memory usage.

Bottom Line:

Every open allocates a small amount of memory that is  generally* NOT released until LV exits. 

Ben

* I have not experimented with explicitly releaseing the memory of the VI to see if it affect the memory usage.

[smercurio_fc]

That little note is not new in LV 2009 - it's been there in earlier versions as well. I think that note is referring to a situation such as this:

Running it in highlight mode indicates a new reference number at the probe. In this case you can't open the reference outside the loop (e.g., if you wire in an array of control references). In this respect I think the note is correct.

Message Edited by smercurio_fc on 08-27-2009 12:31 PM