Used with the switch_type attribute in a union.

  
      [ case(  
   value  
) ]  

value
A possible input value for which you want to provide processing. The type of value can be one of the following types:

• int

• char

• boolean

• enum

or an identifier of such a type.

The case C++ attribute has the same functionality as the case MIDL attribute. This attribute is only used with the switch_type attribute.

The following code shows a use of the case attribute:

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

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

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