This documentation is archived and is not being maintained.


Last modified: January 16, 2009

Applies to: Office 2010 | Outlook 2010 | Visual Studio

Provides an alternative way to invoke the OLE method IUnknown::Release.

Header file:


Implemented by:


Called by:

Client applications and service providers

ULONG UlRelease(
  LPVOID punk


[in] Pointer to an interface derived from the IUnknown interface, in other words any MAPI interface.


The call succeeded and has returned the expected value or values.


An error of unexpected or unknown origin prevented the operation from completing.

The reference count is the number of existing pointers to the object to be released.

If the punk parameter is NULL, the function returns immediately without calling IUnknown::Release

UlRelease returns the value returned by the IUnknown::Release method, which can be equal to the reference count for the object to be released.

For more information about IUnknown::Release, see Implementing the IUnknown Interface.