Notifications

Notifications are values that a setup function sends to a callback routine to specify a state or event. Two parameters, Param1 and Param2, are sent with the notification, and contain additional information relevant to the notification.

The callback routine processes the notification and returns an unsigned integer to the setup function. Depending on the setup function, you can use this value may be used to specify an operation or user selection, or you may ignore it.

The setup functions send notifications to callback routines using the following syntax.

MsgHandler(          //the specified callback routine
    Context,         //context used by the callback routine
    Notification,    //notification code
    Param1,          //additional notification information
    Param2            //additional notification information
);

The Context parameter is a void pointer to a context variable or structure that the callback routine can use to store information that must persist between subsequent calls to the callback routine.

Because the callback routine specifies the context s implementation, and it is never referenced or altered by the setup functions, the context is not documented in the reference material for the notification messages that follow.

The Notification parameter specifies an unsigned integer value for an event or state that causes the setup function to call the callback routine.

Param1 and Param2 are optional parameters that can contain additional information relevant to the notification. These parameters are unsigned integers. If Param1 or  Param2 return information that is not an unsigned integer, it will be cast to an unsigned integer and must be recast to its original data type before it can be used by the callback routine.

Note  The following notifications represent every notification used by the setup functions. Individual functions will use a subset of these notifications. In other words, not every notification is used by every function.

The following notifications are used by the setup functions.