Functions: Callbacks

Using the functions described here, commands can be dynamically added to the system or be removed. You can also register and de-register functions as callbacks for any notifications.

eplRegisterCommandHandler

EplHandle
eplRegisterCommandHandler(EplSession                session,
                          const EplChar*        command,
                          COMMANDCALLBACK        callback);

This function provides the possibility to register external command functions via a command name.

Return Description
EplHandle The function always returns EPL_OK.
Input Type Description
session EplSession Handle of the session in which the external command is to be registered.
command const EplChar* Name under which the command function is to be registered.
callback COMMANDCALLBACK* Pointer to the command function to be registered.

eplUnregisterCommandHandler

EplHandle
eplUnregisterCommandHandler(const EplChar* command);

This function removes a previously registered command from the system. Using this function commands can be written that are only to be available in certain situations.

Return Description
EplHandle This function always returns EPL_OK.
Input Type Description
command const EplChar* Name of the command to be de-registered.

eplRegisterNotificationHandler

EplHandle
eplRegisterNotificationHandler(EplSession                session,
                               const EplChar*                notification,
                               long                        clientdata,
                               NOTIFICATIONCALLBACK        callback);

This function allows for registering a notification handler for a certain notification. Once a handler is registered for a notification, it is called up whenever the notification is sent.

Return Description
EplHandle The function always returns EPL_OK.
Input Type Description
session EplSession Handle of the session in which the notification function is to be registered.
notification const EplChar* Name of the notification for which the notification function is to be registered.
clientdata long Address of user-specific data to be transferred when the notification function is called up.
callback NOTIFICATIONCALLBACK Pointer to the notification function to be registered.

eplUnregisterNotificationHandler

EplHandle
eplUnregisterNotificationHandler(const EplChar*        notification,
                                 NOTIFICATIONCALLBACK        callback);

This function removes a registered notification handler. The handler is then not called up for the notification any more.

Return Description
EplHandle
Input Type Description
notification const EplChar* Name of the notification whose handler is to be removed.
callback NOTIFICATIONCALLBACK Address of the notification handler.