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    • By torekp
      DLL functions or shared variables?  Or something else?
      I have a Labview 2014-64 executable (or I can build a DLL) that runs one piece of equipment, the X-ray.  The other engineer has a large CVI Labwindows 2015 + MS Visual Studio 2012 (C++) executable that runs everything else.  I want the Labview code to be a slave of the CVI code, accepting commands to turn X-ray On or Off, reporting failures, and the like.  Translating the X-ray code into C++ would be possible in principle, but not fun.
      Shared variables look easy, but I'm kinda scared of them.  I would define all the shared variables in my LV code, since I'm more familiar with LV, then use them in both.  There's a thread in here called "Shared Variable Woes" so maybe I should be scared.  In the alternative, I tried building a proof-of-concept DLL in Labview, and calling its functions in CVI/C++, and it works, but it's kinda clunky.  (I'm attaching it below in case you want to play, or advise.)
      Your advice would be appreciated.
    • By Dawid
      I'm trying to execute LPR.exe command to print some labels on a printer. However as its normal, problems occur. I could not find answer on any topic conneced with "sytem exec". I already tried all described methods (I think so). That's why I'm asking very kindly for any help.
      When trying to execute or call the LPR.exe from System exec VI, I'm receiving error:
      "'C:\Windows\System32\lpr.exe' is not recognized as an internal or external command, operable program or batch file."
      Generally I would like to call function: "lpr -S -P lp C:\test\do_druku.txt" which works from command window without any problem.


    • By patufet_99
      To use a controller from LabVIEW I have to use some functions of a DLL.
      For one of the functions, according to the header file .h there is a structure data with parameters of different types that I have to pass to the dll. Some of the parameres are BYTE (1 Byte)  and WORD (2 Bytes).
      When compiling this kind of structure with Visual C++ and looking at it's size with "sizeof()" it seems to me that 4 Bytes variables have to start in a position multiple of 4. For example if there is a BYTE and then a DWORD, the 3 Bytes after the BYTE are ignored and the DWORD starts at Bytes 5 to 8.
      When defining a LabVIEW cluster to match the DLL structure, will LabVIEW do the same? If in my cluster there is a U8 variable and then a U32, will anyway the U8 take 4 bytes?
      Thank you.
    • By torekp
      So I created a DLL from a Labview VI that has a 2D array input (and some scalar inputs) and some 2D array outputs.  Labview creates a .h file with these lines

      And then it defines the 2D array arguments to my function as being of this type: "void __cdecl Linear_discrim_4dll(DoubleArray *dataObsFeat, int32_t grpAsz," etc etc.  Trouble is, I have no idea how to fill out this structure so that the DLL can use it.  Say for simplicity I had a 2 by 3 input called dataObsFeat with elements {1,2,3; 11,12,13}; how would I create the object with these values in C or C++ and pass it to the function?  I am a total C++ noob, in case it isn't obvious.
    • By ensegre
      I wonder if someone ran into this and has a good suggestion about. I have a DSC project, in which it looks just right to organize hierarchically my shared variables. Like, e.g.

      Now this is easy to do programmatically, see the attached project. The problem arises when building an application. It would look as if the plain way to do it, would be to create a build specification which includes the additional libraries, and select their deployment in the "Shared Variable Deployment" tab. However, this doesn't seem to work for nested libraries as in my example. The only possibility seems to add in "Always included" each of the contained libraries. But by doing like this the hierarchy is flattened.
      If I include like this,

      then the variables within the container library are not deployed at runtime.
      In my example project:
      open the project in the IDE, run DeployAllSharedVariables.vi, then CheckDeployed, and see the result (all four variables found with their nested paths) build and run DeployFlatLibraries and see the result: four variables, but flattened paths build and run DeployHierarchicalLibraries: only the two variables in the unnested SimpleVariableLibrary are there. I've searched a bit, and only came up with this document, which (for >2009) says "just check the checkbox". Nor the help page says much either.
      I wonder if I can do what I'd like only compiling separately the libraries, and loading them programmatically afterwards, both in the IDE and in the exe. Which probably is sane, but inconvenient for the first attempts.
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