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4/8/2010

The AddRefmethod increments the reference count for an interface on an object. It should be called for every new copy of a pointer to an interface on a given object.

Syntax 

ULONG AddRef(void);

Parameters

None.

Return Value

Returns an integer from 1 to n, representing the value of the new reference count. This information for diagnostic or testing purposes only because, in certain situations, the value may be unstable.

Remarks

Objects use a reference counting mechanism to ensure that the lifetime of the object includes the lifetime of references to it. You use AddRefto stabilize a copy of an interface pointer. AddRefcan also be called when the life of a cloned pointer must extend beyond the lifetime of the original pointer. The cloned pointer must be released by calling MAPI IUnknown::Release.

Objects must be able to maintain (231)-1 outstanding pointer references. Therefore, the internal reference counter that AddRefmaintains must be a 32-bit unsigned integer.

Call this function for every new copy of an interface pointer that you make. For example, if you are passing a copy of a pointer back from a function, you must call AddRefon that pointer. You must also call AddRefon a pointer before passing it as an in-out parameter to a function; the function calls MAPI IUnknown::Releasebefore copying the out-value on top of it.

Requirements

Header unknwn.h
Windows Embedded CE Windows CE 3.0 and later
Windows Mobile Pocket PC 2002 and later, Smartphone 2002 and later

See Also