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Specifies the expression or identifier acting as the union discriminant that selects the union member.


Attribute Context

Applies to typedef
Repeatable No
Required attributes None
Invalid attributes None

For more information about the attribute contexts, see Attribute Contexts.


The switch_is C++ attribute has the same functionality as the switch_is MIDL attribute.


See the case example for a sample use of switch_is.

See Also

IDL Attributes | Typedef, Enum, Union, and Struct Attributes | switch_type | Attributes Samples