handshaking between programs

[EricS.]

I completely agree, though it never hurts to learn something new if you have the time.  Unfortunately time is hard to come by these days, though.

[JCampos]

Yes the DLL was built with LabVIEW VI's. I will try calling it from LabVIEW itself and report back the results soon.

Thank you for all your help.

[EricS.]

No problem man, it's just a really weird issue.  CVI and LV can communicate with shared variables just fine, but it's interesting to have a LV DLL communicate with them through CVI.

Let us know what happens from LV,

[JCampos]

So after quite some time I have been brought back to this issue and have some new information.

I have a DLL created in LabVIEW that I am trying to access through CVI. In CVI, the function call immediately returns without doing anything. I have another DLL also created in LabVIEW that works just fine when called using CVI. The biggest difference I will point out between the working DLL and non-working one is that the non-working one makes reads and writes to a few shared variables. The executable works just fine but its just the DLL that isn't working.

I have also tried calling the DLL from within a LabVIEW program using the Call Library Function node and I can see the function I want but it shows up with void parameters which is not the case.

Thanks,

Julissa

[Thør]

The next step might be to try making a very simple LabVIEW DLL that reads/writes shared variables and see if the same error crops up.  If this very simple program doesn't work, then we'll definitely have to look into this further.  Additonally, which version of LabVIEW are you using, and which version of CVI?

[JCampos]

I have been able to create a simple LabVIEW DLL that reads/writes to my Shared Variables and have been able to create a CVI program that reads/writes to the same Shared Variables as I have been trying to do and did not see any problem whatsoever with it. I started to add pieces of my larger to that simple DLL to start building up to the final product and found that when I added a timed loop it never worked in the DLL but does in the EXE. I am attaching the simple vi that I have created for this test.

I am using LabVIEW 8.6 and CVI 8.5.

Any ideas??

thanks

[Thør]

Hmm so it seems like the problem doesn't have anything to do with the shared variables then.  Have you tried replacing the timed loop with a standard while loop with a wait function inside?  If this works where the timed loop didn't it's possible you may have found a bug.  Keep me updated on how it's going.

[JCampos]

Kyle,

The while loop with a wait function did work. It opens up just fine just as the exe does. Any possible ideas?

Thanks,

Julissa