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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.
      XrayDLL.zip
    • By 0_o
      Hi,
      This is not specifically LabVIEW related:
      How do you organize important posts you read and want to save for the time of need?
      For example, I want to save an interesting post from Lavag/NI Forums or any other LV blog.
      This post might contain VIs and I would like to tag it in a way that will let me find it when it becomes relevant.
      I would like such a post to be saved locally like an RSS so that I'll get the new comments and won't depend on the site to keep the links alive.
      I see the veterans here keep track of all the new posts and even offer solutions by giving links to some old posts without having to search for them sometimes.
      Do I miss something? How do you organize it all? I hope to hear of some cool little RSS app that will let me search through the tagged vis and posts stored on my computer and not about some bookmark manager.
      Thanks in advance.
       
    • 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 GregFreeman
      I am running calls to a various stored procedures in parallel, each with their own connection refnums. A few of these calls can take a while to execute from time to time. In critical parts of my application I would like the Cmd Execute.vi to be reentrant. Generally I handle this by making a copy of the NI library and namespacing my own version. I can then make a reentrant copy of the VI I need and save it in my own library, then commit it in version control so everyone working on the project has it. But the library is password protected so even a copy of it keeps it locked. I can't do a save as on the VIs that I need and make a reentrant copy, nor can I add any new VIs to the library.
      Does anyone have any suggestions? I have resorted to taking NIs library, including it inside my own library, then basically rewriting the VIs I need by copying the contents from the block diagram of the VI I want to "save as" and pasting them in another VI.
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