Possible enumeration values:
| Name | Value | Description | 
|---|---|---|
| None | 
                     0  | 
                |
| In | 
                     1  | 
                |
| Out | 
                     2  | 
                |
| Lcid | 
                     4  | 
                |
| Retval | 
                     8  | 
                |
| Optional | 
                     16  | 
                |
| HasDefault | 
                     4096  | 
                |
| HasFieldMarshal | 
                     8192  | 
                |
| Reserved3 | 
                     16384  | 
                |
| Reserved4 | 
                     32768  | 
                |
| ReservedMask | 
                     61440  |