Multi instance of function global

[Pnt]

Why not ?

Although i have not tried it...

[JeffOverton]

I believe that if you call them by reference with Option 8, you can ensure that each retains its own data space.

[Wayne.C]

The whole idea of a functional global is that it is a place to hold data in single known place in memory that can only be accessed by one process at a time.  That helps prevent race conditions that can occur with other variables.  If it's reentrant, you don't know where the data is because you don't have control over how many copies that NI creates.

[JeffOverton]

Ah, but if you set the reentrancy to preallocate memory for each clone, it will ensure distinct dataspace for each reference, and the reference will carry the specific instance through.

[Wayne.C]

Jeff,

I think I see what you're getting at.  I'll agree that in the specific instance of using Open VI Reference with option 08 and using the Call By Reference Node that a reentrant functional global should work. 

Anyone else reading this thread just needs to understand that all calls to the reentrant functional global are by reference only and not by calling it directly as a subvi on the block diagram.

[alex.]

I tried something, maybe not correct. I will try to follow your ways.

[alex.]

I use the code attached, tried to generate  aaa and bbb for 2 FG instances output.

[alex.]

I tried the typed reference, but the link seems cannot be connected.

[Ben]

The type gets wired to the top input of the Open.

Ben

[alex.]

Is the "preallocate memory" available in 8.5, since I cannot locate it in 8.2.1

May I know what is option 8.

What I assume is each thread will generate a new instance for FG by VI reference Open. Then wherever need to use the same FG, I just pass the reference to it, no matter inside or outside the port.

The new instance of FG should only be generated when I call it, but now seems cannot make it. So I am a bit confused.

If I use a vit and open it as a reference, will it generate another new copy when I use the same reference to run the FG.