Hi,
I'm currently porting existing Custom Devices that used to run on Phar Lap ETS to Linux RT. The main logic of the custom devices is written in C and there is only LabVIEW "glue-code" to integrate the C code into VeriStand.
So essentially the LabVIEW code consists of different "Call Library Function" nodes. This all works very well but there is one problem I can't solve: How can I unload a shared library from LabVIEW? I'll explain why I need to unload the shared lib.
During the development phase of the custom devices there is a cycle like this:
- Deploy
- Test
- Undeploy
- Change Code, rebuild .so file
- Copy .so to "Public Documents" folder so it will be downloaded to the target during next deployment
- Deploy
- LabVIEW/VeriStand crash
My theory why it crashes is this: The VeriStand Engine is a LabVIEW application that keeps running permanently. So even if you undeploy, shared libraries that were loaded during the previous deployment are still kept in memory. During the next deployment, a different version of the same library is copied to the system, while the old copy is still in memory. LabVIEW doesn't like that and crashes.
This problem could be avoided if there was a way to unload shared libraries during undeployment. According to this link
https://knowledge.ni.com/KnowledgeArticleDetails?id=kA00Z0000019O6eSAE&l=en-US
it can be done by wiring an empty path to all “Call Library Function” nodes. But I have no idea how you would design the LabVIEW code to do that. All custom devices are inline, so in the “Close” case I somehow would have to call all the nodes that are called in the other cases, but this time with an empty path. Any ideas?
Thanks
Dirk
