The following table lists the attributes allowed in interface definition files and specifies the declarations in which they can occur.
IDL Attributes
| Attribute | Where Used |
| uuid version endpoint exceptions pointer_default local |
Interface definition headers |
| broadcast | Operations |
| maybe | |
| idempotent | |
| reflect_deletions | |
| in | Parameters |
| out | |
| ignore | Structures |
| max_is | Arrays |
| min_is | |
| size_is | |
| first_is | |
| last_is | |
| length_is | |
| string | Arrays |
| ptr | Pointers |
| ref | |
| handle | Customized handles |
| context_handle | Context handles |
| transmit_as | Type declarations |