Semaphore problem upon reinitializing VI

[kristofparedis]

And why/where exactly do I want to destroy the semaphore. Because I need it as long as my program is running... so I don't see a reason to destroy it... cause I have to initialize a new one then...

[JÞB]

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kristofparedis wrote:
And why/where exactly do I want to destroy the semaphore. Because I need it as long as my program is running... so I don't see a reason to destroy it... cause I have to initialize a new one then...

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Thats kind of like leaving the front door open when you come home because you "intend to go to work again tomarrow anyway."  Open-close it,  Create it-destroy it, are good code practices and help your code be more self-contained.  You don't allways want to rely on an OS garbage collection to clean up for you.

[kristofparedis]

ok, makes sense.

Thanks Jeff. 

Now concerning my initial question. Say that I do need to work with a local for my reference. Is there any way to work around the issue, e.g. is there a way to switch off the reinitialization for the locals, or to put the correct value back in (by recreating a new semaphore), so that my program can continue? Because I guess that the value of the local gets deleted and the acquire function gives an error because it can't read the local any more... right?

Kristof

[JÞB]

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kristofparedis wrote:

ok, makes sense.

Thanks Jeff. 

Because I guess that the value of the local gets deleted and the acquire function gives an error because it can't read the local any more... right?

 Correct

Kristof

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Now concerning my initial question. Say that I do need to work with a local for my reference.

You NEVER have to work with a local variable (OK I have used them but, very rarely)

there is a community nugget on FG's and AEs that  Ben wrote.  It will give you an idea how you can store that semaphore in a sub-vi and access it from anywhere.  Wires would be the "prefered" method of passing the referance to the data though.

[kristofparedis]

Thank you,

One more thing on your last comment: you never have to use locals and then I consider my case solved 🙂

I was trying to see whether I could get rid of all my locals in my program, but say I have 3 for loops in a sequence, each generating a certain amount of data, one after the other. In my current program, I write everything I collect into a local and with a seperate while loop I pick-up the data and plot them continuously. How do you managae this without a local (since the for loop only passes it data to the next when it is finished). So i can basically only plot in 3 steps all the data from one loop at a time, instead of point by point.

Kristof

[JÞB]

Check out queues and Producer consumer loops.  Much faster!  however you can pass the data out of a loop in a FG.