Release 10.1A: OpenEdge Development:
Programming Interfaces

> ## Validating component handles

> If you reference a `COM-HANDLE` variable whose value does not point to a valid COM object, Progress returns an error indicating that an action was performed on an invalid `COM-HANDLE`. To protect against this error, use the Progress `VALID-HANDLE` function to determine if the `COM-HANDLE` variable contains a valid value before using it in any other Progress statement. As with widget handles, the `VALID-HANDLE` function returns `TRUE` if the component handle is valid.

> Note that you cannot use the `VALID-HANDLE` function to verify that a component handle value points to a particular COM object. `COM-HANDLE` values might be reused within an application when the COM objects they point to are no longer available. For more information, see the "Managing COM object resources" section.

> Also, this function only indicates that a component handle is invalid from some action (or inaction) of the OpenEdge application. It does not show as invalid a COM handle that a user might have manually closed, for example, an Automation Server application that provided the COM object.

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