Choosing my Runtime Engine

[DanLL2020]

Hi,

I recently upgraded the runtime engine on my machine from 2017 to 2019 so that I could run the latest version of my test program. This has been working fine but today I tried to run a separate test program and received the error 'You cannot open a packed library saved in a version earlier than the current version of LabVIEW'. I think the packed library was compiled in LabVIEW 2017 so this is what's causing the error.

I don't have the source code for this packed library so I can't open it and recompile it in LabVIEW 2019. I have both the 2019 Runtime Engine and 2017 Runtime Engine installed on the machine though. Would it be possible to set up the machine so that it uses Runtime 2019 to run the first test program and Runtime 2017 to run the separate program?

I've searched the forums for something about this but haven't had much luck. I'd appreciate any recommendations you could give me.

Cheers,

Dan

[cbutcher]

Hi Dan,

There are two things here:

• If in future you have influence over the author/builder of the packed library, then since 2017 we can set PPLs to be forward compatible (I.e. Compile in 17, open in 17, 18, 18, 20...)
• The runtime chosen will depend on the version of LabVIEW you build your application with. So if the same test program is being used for both, then compiling it twice is one option (but not a very nice one). Remaining in 2017 might also be an option, depending on if you require newer features or not...

Take a look here for more details: https://www.ni.com/en-gb/support/documentation/compatibility/17/labview-and-labview-run-time-engine-...

The faded green bits show the forward compatibility option.

[DanLL2020]

Hi cbutcher,

Thanks for this compatibility info. I think the packed library was built in 2017 but we probably didn't set it to be forward compatible so it doesn't work with our 2019 runtime. I think we'll just have to make sure we do it from this point onward.

Since I don't have the packed library source code, I'll just have to write the code again in LabVIEW 2019. Hopefully this won't take too long.

[crossrulz]

Another warning.  You can also set your executable to run in a newer runtime engine.  That executable will run in the newest RTE installed.  If your PPLs were not also compiled with that option, you will have errors.  Yes, I recently ran into this issue.

[DanLL2020]

Thanks crossrulz, I'll make sure I use this option in the future.