switch_type

[アーティクル]
01/03/2018

The latest version of this topic can be found at switch_type.

Identifies the type of the variable used as the union discriminant.

Syntax

  
[switch_type(  
type  
}]

Parameters

type
The switch type, can be an integer, character, Boolean, or enumeration type.

Remarks

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

C++ attributes do not support encapsulated unions. Nonencapsulated unions are supported only in the following form:

// cpp_attr_ref_switch_type.cpp  
// compile with: /LD  
#include <windows.h>  
[module(name="MyLibrary")];  
[ export ]  
struct SizedValue2 {  
   [switch_type("char"), switch_is(kind)] union {  
      [case(1), string]  
         wchar_t* wval;  
      [default, string]  
         char* val;  
   };  
   char kind;  
};

Example

See the case example for a sample use of switch_type.

Requirements

Attribute Context

Applies to	`typedef`
Repeatable	No
Required attributes	None
Invalid attributes	None

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

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