A list of the functions currently called to perform special actions, including the one just added.
When some objects are garbage collected, you may require a "special action" to be performed as well.
adds the function
to perform the special action. Note that the function is applied to all objects flagged for special-free-action, so the function
should check for the object's type, so that it only affects relevant objects.
LispWorks User Guide and Reference Manual - 21 Dec 2011