nsISupports

From MDC

« XPCOM API Reference

[edit] Summary

All XPCOM interfaces inherit the nsISupports interface.

#include "nsISupports.h"

[scriptable, uuid=(0000000-0000-0000-c000-000000000046)]
interface nsISupports { ... };

[edit] Methods

AddRef

The AddRef method notifies the object that an interface pointer has been duplicated.

QueryInterface

The QueryInterface method provides runtime type discovery.

Release

The Release method notifies the object that an interface pointer has been destroyed and any resources the object held on behalf of the client can be released.

[edit] Remarks

The method descriptions above were taken from Essential COM by Don Box. The point of those descriptions is to highlight the fact that Addref and Release do not necessarily correspond to incrementing and decrementing a counter, respectively, even though that is how they are usually implemented.

On Win32 systems, nsISupports is ABI-compatible with Microsoft COM's IUnknown interface.