pointers

MIDL supports three kinds of pointers: reference pointers, unique pointers, and full pointers. These pointers are specified by the pointer attributes ref, unique, and ptr.

A pointer attribute can be applied as a type attribute; as a field attribute that applies to a structure member, union member, or parameter; or as a function attribute that applies to the function return type. The pointer attribute can also appear with the pointer_default keyword.

To allow a pointer parameter to change in value during a remote function, you must provide another level of indirection by supplying multiple pointer declarators. The explicit pointer attribute applied to the parameter affects only the rightmost pointer declarator for the parameter. When there are multiple pointer declarators in a parameter declaration, the other declarators default to the pointer attribute specified by the pointer_default attribute. To apply different pointer attributes to multiple pointer declarators, you must define intermediate types that specify the explicit pointer attributes.