Each COM interface pointer has a reference count which is used by the server to control its lifetime. The function release
should be called whenever a reference to the interface pointer is being removed. The function invokes the COM method IUnknown::Release
so the form (release ptr)
is equivalent to using call-com-interface
as follows:
(call-com-interface (ptr i-unknown release))
LispWorks COM/Automation User Guide and Reference Manual - 14 Feb 2015