Creating Custom Command Line Operations

LabVIEW 2018 Help


Edition Date: March 2018
Part Number: 371361R-01
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To create a custom command line operation to run in the command line interface (CLI) for LabVIEW, complete the following tasks:

  • Part 1: Define the operation name.
  • Part 2: Define the operation behavior.
  • Part 3 (Optional): Define the help for the operation.

Part 1: Defining the Operation Name

In the CLI for LabVIEW, command line operations have a parent class and each operation is built from a child class of the parent class. To define the name of the operation, you must create a child class of the parent class and specify the name of the child class.

Complete the following steps to define the name of the operation:

  1. Navigate to one of the following directories:
    • (Windows) C:\Program Files (x86)\National Instruments\Shared\LabVIEW CLI\Operations
    • (macOS) /Library/Application Support/National Instruments/LabVIEW CLI/Operations
    • (Linux) /usr/local/natinst/nilvcli/Operations
  2. Open Operations.lvproj or Toolkit-Operations.lvproj, depending on whether the operation requires the LabVIEW development system only or additional LabVIEW modules and toolkits.
  3. Right-click My Computer and select New»Class.
  4. In the New Class window, specify the name of the class, such as AddNum. The class name is the name of the operation you are creating.
  5. In the project tree, right-click the class that you created and select Properties.
  6. On the Inheritance page, click Change Inheritance.
  7. Select CoreOperation.lvclass, click Inherit from Selected, and click OK.

Part 2: Defining the Operation Behavior

To define the behavior of the operation, you must override the methods of the class you created in the previous section and add code in one of the overridden methods.

Complete the following steps to define the behavior of the operation:

  1. In the project tree, right-click the class that you created in the previous section and select New»VI for Override.
  2. In the New Override window, select GetHelp.vi and RunOperation.vi, and click OK.
  3. Save the project. When prompted, save the class and the overridden methods in a folder with the same name as the operation.
    Note  NI recommends that you put the folder in one of the following directories so that you do not need to specify the path to the folder using the −AdditionalOperationDirectory argument when running the operation.
    • (Windows) C:\Program Files (x86)\National Instruments\Shared\LabVIEW CLI\Operations
    • (macOS) /Library/Application Support/National Instruments/LabVIEW CLI/Operations
    • (Linux) /usr/local/natinst/nilvcli/Operations
  4. Open the block diagram of the RunOperation.vi method.
  5. Remove and rewire the subVI.
  6. Add code to define the behavior of the operation and save your changes. Do not modify the connector pane, as illustrated in the following figure.



    TerminalData TypeDescription
    LabVIEW object of the class that you created in the previous section.
    Arguments that users enter in the CLI for LabVIEW when running this operation. Each string in the array represents an argument.
    LabVIEW object of the class that you created in the previous section.
    A code that the CLI for LabVIEW returns to the calling application, such as a Jenkins application. For example, you can configure the CLI for LabVIEW to return 0 if the operation runs successfully and -1 if an error occurs.
    Output of the operation or error messages to display in the CLI for LabVIEW console or to save to the log file.

    Refer to RunOperation.vi in one of the following directories for an example of defining the behavior of the AddNum operation, which adds two input numbers and returns the sum in the output.
    • (Windows) C:\Users\Public\Documents\National Instruments\LabVIEW CLI\Examples\AddNum
    • (macOS) /Library/Application Support/National Instruments/LabVIEW CLI/Examples/AddNum
    • (Linux) /usr/local/natinst/nilvcli/Examples/AddNum

Part 3: Defining the Help for the Operation

To help users get started using the operation, you can document the operation by modifying the GetHelp.vi method that you created in the previous section. Users can then access the documentation by executing the LabVIEWCLI -OperationName <operation name> -Help command.

Complete the following steps to document the operation:

  1. Open the GetHelp.vi method from the project tree.
  2. On the front panel, create a string control named Help and enter the documentation in this control.
  3. Right-click the Help control and select Data Operation»Make Current Value Default to set the current text as the default value of this control. Repeat this step each time you edit the text.
  4. On the block diagram, remove and rewire the subVI.
  5. Wire the objects in the following way, where AddNum is the operation name, and save your changes.

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