trusty (3) alarm_handler.3erl.gz

NAME

       alarm_handler - An Alarm Handling Process

DESCRIPTION

       The  alarm handler process is a gen_event event manager process which receives alarms in the system. This
       process is not intended to be a complete alarm handler. It defines a place to which alarms can  be  sent.
       One simple event handler is installed in the alarm handler at start-up, but users are encouraged to write
       and install their own handlers.

       The simple event handler sends all alarms as info reports to the error logger, and saves all of them in a
       list  which  can  be passed to a user defined event handler, which may be installed at a later stage. The
       list can grow large if many alarms are generated. So it is a good reason to install a better user defined
       handler.

       There  are  functions to set and clear alarms. The format of alarms are defined by the user. For example,
       an event handler for SNMP could be defined, together with an alarm MIB.

       The alarm handler is part of the SASL application.

       When writing new event handlers for the alarm handler, the following events must be handled:

         {set_alarm, {AlarmId, AlarmDescr}}:
           This event is generated by alarm_handler:set_alarm({AlarmId, AlarmDecsr}).

         {clear_alarm, AlarmId}:
           This event is generated by alarm_handler:clear_alarm(AlarmId).

       The  default  simple  handler  is  called  alarm_handler   and   it   may   be   exchanged   by   calling
       gen_event:swap_handler/3  as  gen_event:swap_handler(alarm_handler,  {alarm_handler,  swap}, {NewHandler,
       Args}). NewHandler:init({Args, {alarm_handler, Alarms}}) is called. Refer to gen_event(3erl) for  further
       details.

EXPORTS

       clear_alarm(AlarmId) -> void()

              Types:

                 AlarmId = term()

              Clears all alarms with id AlarmId.

       get_alarms() -> [alarm()]

              Returns  a  list  of  all active alarms. This function can only be used when the simple handler is
              installed.

       set_alarm(alarm())

              Types:

                 alarm() = {AlarmId, AlarmDescription}
                 AlarmId = term()
                 AlarmDescription = term()

              Sets an alarm with id AlarmId. This id is used at a later stage when the alarm is cleared.

SEE ALSO

       error_logger(3erl), gen_event(3erl)