LVOOP Property Nodes and DVRs

[PaulL]

I just encountered (this?) issue with property nodes for accessor methods as well. (I don't use Data Value References, for the record. I know those have already been exonerated in this thread.)

There is no still no mention of either CAR on the known issues page.

Anyway, I set up a part of my application to deploy and run on my real-time target, and it mostly crashes after deployment but before execution, but sometimes runs. (It always runs fine on Windows, by the way.) I deleted all the property node accessor methods from the classes, recreated regular accessor methods, and the test VI now runs fine....

Bummer! I really like the property node accessor method feature. I don't have to edit accessor method icons (really not fun), I can read or write more than one accessor method at a time, and I don't even have to find the accessor method in the project. I look forward to using the fixed version!

[PaulL]

For the record, the CAR for the issue I reported is 279298.

I also forgot to mention that I would especially like to use the property node accessor feature because I they don't look like VIs so it is quicker to see what is happening in the calling VIs....

[Tomi Maila]

I am not quite sure if this is a related bug but I noticed incorrect behavior with property nodes when uses w/o DVRs. Basically the property node breaks for a child class if only one accessor has an override method. I wrote a post on NI forums.

http://forums.ni.com/t5/LabVIEW/Class-properties-of-decedent-class-access-scope-error/m-p/1399220#U1399220

Tomi

[Tomi Maila]

Just had a strange behavior with a property node. Class wire was wired to a property node with 4 read properties. The value of the class wire (non-DVR) was right according to the probe just before the property node. There was a private data called DBL one of the read properties accessed. When the property node executed, the accessor was executed, but the object flowing from the input terminal of the accessor was the default value of the class, not the value of the wire connected to the property node. The property node returned incorrect value i.e. the default value. When the property node was replaced with a read accessor, it worked properly. When I replaced the read accessor again with a property node, it worked properly. So it seems that there is some, possibly optimization, that takes place, and the result of which, the accessor does not get executed with proper input buffer wired to its input terminal. This would not happen normally, but under some rare circumstances where possibly the classes have hanged when the property node already was placed on the block diagram.

Tomi

[Mr Mike]

Just had a strange behavior with a property node. Class wire was wired to a property node with 4 read properties. The value of the class wire (non-DVR) was right according to the probe just before the property node. There was a private data called DBL one of the read properties accessed. When the property node executed, the accessor was executed, but the object flowing from the input terminal of the accessor was the default value of the class, not the value of the wire connected to the property node. The property node returned incorrect value i.e. the default value. When the property node was replaced with a read accessor, it worked properly. When I replaced the read accessor again with a property node, it worked properly. So it seems that there is some, possibly optimization, that takes place, and the result of which, the accessor does not get executed with proper input buffer wired to its input terminal. This would not happen normally, but under some rare circumstances where possibly the classes have hanged when the property node already was placed on the block diagram.

Tomi

That sounds like another one of the symptoms of the CAR Jon Kokott found (248637). Please let me know (private message is fine) if you are able to reliably reproduce it.

[Jon S]

For the record, the CAR for the issue I reported is 279298.

I also forgot to mention that I would especially like to use the property node accessor feature because I they don't look like VIs so it is quicker to see what is happening in the calling VIs....

Thanks for the Info Paul. We believe that the underlying solution to CAR 279298 is the same as CAR 255982. So when these bugs get fixed if there are any special instructions in the readme (possibly recompiling) about CAR 255982 you should apply them to CAR 279298 as well

FYI: Both of these should now show up in the LabVIEW Known Issues even if they are specific to RT.

[PaulL]

Thanks for the Info Paul. We believe that the underlying solution to CAR 279298 is the same as CAR 255982. So when these bugs get fixed if there are any special instructions in the readme (possibly recompiling) about CAR 255982 you should apply them to CAR 279298 as well

FYI: Both of these should now show up in the LabVIEW Known Issues even if they are specific to RT.

Great! Thanks!