Adding an Error
Defining custom errors in an IVI driver allows you to return errors with a proper COM HRESULT and a properly formatted error message that can be displayed by various COM-aware IDEs. Internally, the errors and warnings defined for a particular driver are managed as members of a special enum created in the type library. Typically, the enum that houses all of the driver’s error and warning code definitions has a name that ends with ErrorCodesEnum.
To add an IVI-COM error to a driver
Section titled “To add an IVI-COM error to a driver”-
From Solution Explorer, double-click the Driver Designer node under the Nimbus node.
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The Driver Designer opens as a tabbed document window. Select the IVI-COM tab.
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From the tree view expand the type library node for the instrument-specific hierarchy. This node is named “
\<driverName\>Lib”. -
Right-click on the Errors node and choose Add Error.
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A new error is added with a default name and the tree node enters edit mode.
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With the error node still in edit mode, type the desired name of the error and hit the Enter key.
When choosing an error name, the following naming rules apply:
- The name must be unique within the driver.
- The name must contain only alphanumeric characters and the underscore (
_) character. - Spaces are not allowed.
- The name must be uppercase.
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After the error is added, the IVI-COM Error General Editor appears in the right portion of the IVI-COM Designer. See the help topic for that Item Editor for details on defining the error further.
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If IVI-C wrapper generation is enabled on the IVI-C Page of the Driver Settings Editor, then an IVI-C error is automatically created at this time and associated with the IVI-COM error.
To view the linked IVI-C error, right-click the IVI-COM error, and choose Go to IVI-C Error.
To remove the linked IVI-C error, thereby creating an IVI-COM-only error, right-click the IVI-COM error, and choose Delete IVI-C Error.