[ uuid (87E5BFA0-CA46-1067-B31B-00DD010662DA),
  version(1.0),
  pointer_default(unique)
]
interface dunion
{

typedef [switch_type(short)] union {
    [case(0)] short          sVal;
    [case(1)] float          fVal;
    [case(2)] unsigned char  chVal;
    [default] ;
} DISCRIM_UNION_PARAM_TYPE;

typedef DISCRIM_UNION_PARAM_TYPE DISCRIM_UNION_FIELD_TYPE;

typedef struct {
    short                                          sDiscrim; 
    [switch_is(sDiscrim)] DISCRIM_UNION_FIELD_TYPE u;
} DISCRIM_UNION_STRUCT_TYPE;


void UnionParamProc([in] handle_t h1,
    [in, switch_is(sDiscrim)] DISCRIM_UNION_PARAM_TYPE *UnionParam,
    [in]                      short                    sDiscrim
    );

void UnionStructProc([in] handle_t h1,
    [in] DISCRIM_UNION_STRUCT_TYPE *UnionStruct);

void Shutdown([in] handle_t h1);

}