Notify Objects


A thread uses a Notify object to wait for event notification. For each thread intended to wait for events from an object (or objects), your application must create a Notify object. The source of firmware events are Motion, Sequence, and Recorder objects.

When it is desired to wait for event notifications from a single source, that source (i.e., object handle) can be passed as the second argument to mpiNotifyCreate. After a Notify object is appended to the EventMgr list of Notify objects, make a call to mpiNotifyEventWait to instruct the Notify object to wait for event notification.

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Notify objects maintain a FIFO ("First In, First Out") buffer of events that have occurred. Each call to mpiNotifyEventWait removes one event from the buffer. If the event buffer is empty, mpiNotifyEventWait(...) will wait for an event to be sent to the Notify object. This ensures that events will not be missed in cases where multiple events have occurred between calls to mpiNotifyEventWait(...). However, the danger is that an application may not call mpiNotifyEventWait(...) for a long time. In this case, the event buffer may grow rather quickly and use a large amount of system memory. In order to prevent this problem from occurring, one should use mpiNotifyEventMaskSet to enable and disable event notification at the proper times.



Create, Delete, Validate Methods
  mpiNotifyCreate Create a Notify object
  mpiNotifyDelete Delete a Notify object
  mpiNotifyValidate Validate a Notify object

Event Methods
  mpiNotifyEvent Check to see if events have occurred
  mpiNotifyEventFlush Flush pending events from event queue
  mpiNotifyEventMaskGet Get event mask
  mpiNotifyEventMaskSet Set event mask
  mpiNotifyEventWait Get next event from queue or wait timeout msec for it to arrive
  mpiNotifyEventWake Wake up thread waiting for notify object

Relational Methods
  List Methods for Event Sources
  mpiNotifySource Get the indexth event source in list
  mpiNotifySourceAppend Append an event source to list
  mpiNotifySourceCount Count number of event sources in list
  mpiNotifySourceFirst Get first event source in list
  mpiNotifySourceIndex Get index value for event source in list
  mpiNotifySourceInsert Place event source after source in list
  mpiNotifySourceLast Get last event source in list
  mpiNotifySourceListGet Get list of event sources
  mpiNotifySourceListSet Create a list of event sources
  mpiNotifySourceNext Get next event source after source in list
  mpiNotifySourcePrevious Get the event source before source in list
  mpiNotifySourceRemove Remove event source from list


Data Types