+
+/** \brief Send signal to stop concurrently running memif_poll_event().
+
+ The function, however, does not wait for memif_poll_event() to stop.
+ memif_poll_event() may still return simply because an event has occured
+ or the timeout has elapsed, but if called repeatedly in an infinite loop,
+ a canceled memif_poll_event() is guaranted to return MEMIF_ERR_POLL_CANCEL
+ in the shortest possible time.
+ This feature was not available in the first release.
+ Use macro MEMIF_HAVE_CANCEL_POLL_EVENT to check if the feature is present.
+
+ \return memif_err_t
+*/
+#define MEMIF_HAVE_CANCEL_POLL_EVENT 1
+int memif_cancel_poll_event ();