Offset Size Contents
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  +0       4  pfrNext      address of next SwCallbackInfoRec in the
                           notification chain (or 0000:0000 if last entry)
  +4       4  pfHandler    addr of notification-function handler
  +8       4  res          (reserved)
 +0c       4  pfarAPIs     address of list of SwApiInfoRec structures.
          16               size of an SwCallbackInfoRec structure

     pfrNext  this is the address of the next SwCallbackInfoRec in the
              chain; it is stored by programs which intercept INT 2fH 4b01H
              (build notification chain).

   pfHandler  the FAR address of the code that will be called for various
              notification functions.

    pfarAPIs  the FAR address of the first of a series of SwApiInfoRec
              structures that identify how much support this program
              provides for various asynchronous request APIs.  The list ends
              when the first field of that structure is 0000H.

 This structure is used in SwSrvcFn 0004H (hook notification chain) and in
 INT 2fH 4b01H (build notification chain).  It is part of the system that
 allows programs to be notified when they are about to be switched out or
 that they can resume operation, etc.

See Also: Switcher Services and Notifications
          INT 2fH 4bxxH (switcher functions)