How does LabView 8 handle Ring constants?

Question

Hi all,
This is probably more for NI guys, but I am wondering how LabView 8 handles text rings?  In the past, constants dropped into a VI that are of type "enum" will be updated when the typedef is updated, however, ring text constants will not.  Has this changed in LabView 8?
Thanks,
Jason

Answer 1

Part 1 of 2
Hi Chris,
Please forgive me for differing on this point but you should have written
When a control is strictly typed it will force all  [front panel] instances to be identical to the strict type definition and update all of the text constants.
The "strict" part only takes care of the appearence and those changes only affect instance were they are seen by a user. The strings associated with the enum do not affect block diagram constants.
The attached image and zip illustrates that the representation of an enum and a ring a very different. An enum has the defined strings "hidden" in the wire and the numeric value can only be one of the valid indexes of the defined strings. In this example I have shown three different constructs that illustrate the fundemental difference between rings and enums.
1) Case Structures - An enum driven case will pickup the valid choices as defined by the enum's definition. A ring does not carry this info in the wire so it is NOT possible to label the cases to match the ring. This brings up another compliation. If the case structure does not have a default case defined there must be a case for each possible selection value. The strings of an ring can be defined at run-time. Is LV supposed to re-compile the case structures code every time the ring is re-populated? In the case of an enum driven case, this is not an issue because enums that are used in a VI that is running or reserved to run can not be editied.
2) The "Format into string" can pick-up the valid enum strings by decoding the type descriptor of the enum wire. This is not the case with a ring because the ring is just a number.
3) The "Flatten into string" function will return the type destriptor of whatever is wired to it. The typed descriptor contents of a enum shows that every valid selection for that enum is defined in the enum wire. Please note that the type descriptor for a ring has no information about any strings.
End of part 1 of 2
Ben
Message Edited by Ben on 10-15-2005 10:41 AM
Ben Rayner
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Attachments:
ring vs enum.JPG ‏78 KB