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


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.

Attribute Context

Applies totypedef
Required attributesNone
Invalid attributesNone

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

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