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alarm_handler(3erl) [linux man page]

alarm_handler(3erl)					     Erlang Module Definition					       alarm_handler(3erl)

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_han-
       dler(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)

Ericsson AB							   sasl 2.1.9.3 					       alarm_handler(3erl)

Check Out this Related Man Page

alarm(2)							   System Calls 							  alarm(2)

NAME

       alarm - schedule an alarm signal

SYNOPSIS

       #include <unistd.h>

       unsigned int alarm(unsigned int sec);

DESCRIPTION

       The alarm() function causes the system to generate a SIGALRM signal for the process after the number of real-time seconds specified by sec-
       onds  have  elapsed (see  signal.h(3HEAD)). Processor scheduling delays may prevent the process from handling the signal as soon as  it	is
       generated.

       If seconds is 0, a pending alarm request, if any, is cancelled.

       Alarm requests are not stacked; only one SIGALRM  generation can  be  scheduled in this manner; if the SIGALRM signal has not yet been gen-
       erated, the call will result in rescheduling the time at which the SIGALRM signal will be generated.

       The fork(2) function clears pending alarms in the child process. A new process image created by one of the exec functions inherits the time
       left to an alarm signal in the old process's image.

RETURN VALUES

       If  there  is  a previous alarm request with time  remaining, alarm() returns  a  non-zero  value  that	is the number of seconds until the
       previous request would  have  generated	a SIGALRM signal.  Otherwise, alarm() returns 0.

ERRORS

       The alarm() function is always successful; no return value is reserved to indicate an error.

ATTRIBUTES

       See attributes(5) for descriptions of the following attributes:

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Standard			   |
       +-----------------------------+-----------------------------+
       |MT-Level		     |Async-Signal-Safe 	   |
       +-----------------------------+-----------------------------+

SEE ALSO

       exec(2), fork(2), signal.h(3HEAD), attributes(5), standards(5)

SunOS 5.10							    7 Jun 2001								  alarm(2)
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