Overview

Module esysevent

• Description
• Data Types
• Function Index
• Function Details

Description

Subscribes to system event channels on illumos

This module will only compile and run on illumos/Solaris systems.

The most common use of this module is to subscribe to notifications about zone status changes, with channel com.sun:zones:status.

Example:

  1> {ok, Hdl, MsgRef} = esysevent:evc_subscribe("com.sun:zones:status", [], "testing", all).
  {ok,#Ref<0.2937418369.3205890050.177596>,
      #Ref<0.2937418369.3205758978.177595>}
  2> flush().
  Shell got {sysevent,#Ref<0.2937418369.3205758978.177595>,
                      #{class => <<"status">>,seq => 172,
                        subclass => <<"change">>,time => 4745966022729317},
                      #{<<"newstate">> => {string,<<"initialized">>},
                        <<"oldstate">> => {string,<<"uninitialized">>},
                        <<"when">> => {uint64,4745966022720511},
                        <<"zoneid">> => {int32,1},
                        <<"zonename">> => {string,<<"testzone">>}}}
  

Data Types

bind_flags()

bind_flags() = [create | hold_pending | hold_pending_indefinitely]

channel()

channel() = iolist()

String, e.g. com.sun:zones:status

class()

class() = all | iolist()

Class name

err_result()

err_result() = {error, {func(), errno(), string()}} | {error, term()}

errno()

errno() = integer()

System errno value

ev_attrs()

ev_attrs() = nvlist()

ev_info()

ev_info() = #{class => binary(), subclass => binary(), seq => integer(), time => integer()}

event_msg()

event_msg() = {sysevent, msgref(), ev_info(), ev_attrs()}

Format of a message received by an event subscriber.

func()

func() = atom()

handle()

handle() = reference()

Reference to an EVC handle. Note that if this term gets garbage-collected, the subscription will be automatically cancelled. Subscribers are advised to store it in process state until it is no longer required.

msgref()

msgref() = reference()

Unique reference included in event messages for a given subscription

nv_int_type()

nv_int_type() = byte | int8 | uint8 | int16 | uint16 | int32 | uint32 | int64 | uint64

nv_val()

nv_val() = {boolean, boolean()} | {nv_int_type(), integer()} | {string, iolist()} | {array, nv_int_type(), [integer()]} | {array, boolean, [boolean()]} | {array, string, [iolist()]} | {hrtime, integer()} | {nvlist, nvlist()} | {array, nvlist, [nvlist()]}

nvlist()

nvlist() = #{binary() => nv_val()}

The general format of an nvlist_t, converted to an Erlang map.

subid()

subid() = iolist()

Subscriber name, needs to be unique (include PID or something random)

Function Index

Function Details

evc_subscribe/4

Subscribe to an event channel

See also: bind_flags(), channel(), class(), event_msg(), handle(), subid().

evc_unsubscribe/1

Cancel a subscription to an event channel

See also: handle().

Overview

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