Creating a Sequence File Translator DLL

TestStand 2019 Help

Edition Date: May 2019

Part Number: 370052AA-01

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TestStand can load custom sequence files if an existing translator can read and convert the file into a TestStand SequenceFile object. Translators are Microsoft Windows DLLs you can create that export required C callback functions TestStand uses to translate files.

You can create custom sequence file translators in any development environment that can create a Windows DLL with the required C callback functions. National Instruments recommends using the translator examples written in LabVIEW, LabWindows/CVI, and Microsoft Visual C++ as a guide. Each example in the <TestStand Public>\Examples\Fundamentals\Sequence File Translators - Examples directory includes a template project, which contains source code with empty callback functions you must export from the translator DLL. You must add the necessary code to the required callbacks to ensure that the translator properly integrates with TestStand.

When an application loads the TestStand Engine, TestStand loads the DLLs that export the required callback functions from the <TestStand>\Components\Translators directory and the <TestStand Public>\Components\Translators directory. When you run a TestStand sequence file translator example, located in the <TestStand Public>\Components\Translators directory, the example copies the example translator DLL to the <TestStand Public>\Examples\Fundamentals\Sequence File Translators - Examples directory, and you must restart the application before you can use the translator.

\To create new translator DLLs, add the project for the translator in the <TestStand Public>\Components\Translators directory and ensure that the project saves the DLL to the <TestStand Public>\Components\Translators directory. Storing new and customized files in the <TestStand Public> directory ensures that newer installations of the same version of TestStand do not overwrite the customizations and ensures that uninstalling TestStand does not remove the files you customize.

A translator DLL can contain one or more translators. When TestStand loads a translator DLL, TestStand uses the callback functions of the DLL to obtain information about the translators the DLL contains. TestStand calls the CanTranslate callback function to determine whether the DLL contains a translator that recognizes a file. The callback returns the index of the translator that recognizes the file after examining the extension of the file and the contents of the file, typically the file header. Most of the callback functions the translator DLL implements contain an index parameter, which references a specific translator in the DLL that must operate on a file.

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