MI_PROC_CALLBACK modifier (Windows)

The MI_PROC_CALLBACK modifier on a callback definition is required for callbacks that execute with Windows™ applications. For all other operating systems, this modifier is optional. To make callbacks portable between operating systems, include the MI_PROC_CALLBACK modifier in your callback declaration.

The MI_PROC_CALLBACK modifier follows the callback return type and precedes the callback name. A sample callback declaration shows the location of the MI_PROC_CALLBACK modifier in the declaration of the myhandler() callback.