Manual Pages for UNIX Operating System command usage for man sysevent_subscribe_event

System Event Library Functions
                              sysevent_subscribe_event(3SYSEVENT)



NAME
     sysevent_subscribe_event,    sysevent_unsubscribe_event    -
     register or unregister interest in event receipt

SYNOPSIS
     cc  [ flag... ] file... -lsysevent [ library... ]
     #include 

     int sysevent_subscribe_event(sysevent_handle_t *sysevent_hdl,
          char *event_class, char **event_subclass_list,
          int num_subclasses);


     void sysevent_unsubscribe_event(sysevent_handle_t *sysevent_hdl,
          char *event_class);


PARAMETERS
     event_class            system event class string


     event_subclass_list    array of subclass strings


     num_subclasses         number of subclass strings


     sysevent_hdl           sysevent subscriber handle


DESCRIPTION
     The  sysevent_subscribe_event()   function   registers   the
     caller's  interest  in  event notifications belonging to the
     class  event_class   and   the   subclasses   contained   in
     event_subclass_list.   The subscriber handle sysevent_hdl is
     updated with the new subscription and  the  calling  process
     receives  event  notifications from the event handler speci-
     fied in sysevent_bind_handle.


     System events matching event_class and a subclass  contained
     in  event_subclass_list  published  after the caller returns
     from  sysevent_subscribe_event()  are   guaranteed   to   be
     delivered  to  the  calling process.  Matching system events
     published    and    queued    prior    to    a    call    to
     sysevent_subscribe_event() may be delivered to the process's
     event handler.


     The num_subclasses argument provides the number of  subclass
     string elements in event_subclass_list.



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System Event Library Functions
                              sysevent_subscribe_event(3SYSEVENT)



     A caller can use the event class EC_ALL to subscribe to  all
     event classes and subclasses. The event class EC_SUB_ALL can
     be used to subscribe to all subclasses within a given  event
     class.


     Subsequent calls to sysevent_subscribe_event()  are  allowed
     to  add  additional  classes  or  subclasses.   To remove an
     existing subscription, sysevent_unsubscribe_event() must  be
     used to remove the subscription.


     The sysevent_unsubscribe_event() function removes  the  sub-
     scription  described by event_class for sysevent_hdl.  Event
     notifications matching event_class will not be delivered  to
     the calling process upon return.


     A caller can use the event class EC_ALL to remove  all  sub-
     scriptions for sysevent_hdl.


     The library manages all subscription resources.

RETURN VALUES
     The sysevent_subscribe_event() function  returns  0  if  the
     subscription  is  successful.  Otherwise, -1 is returned and
     errno is set to indicate the error.


     The sysevent_unsubscribe_event() function returns no value.

ERRORS
     The sysevent_subscribe_event() function will fail if:

     EACCES    The calling process  has  an  ID  other  than  the
               privileged user.


     EINVAL    The sysevent_hdl argument is an  invalid  sysevent
               handle.


     ENOMEM    There is insufficient memory available to allocate
               subscription resources.


EXAMPLES
     Example 1 Subscribing for environmental events

       #include 



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System Event Library Functions
                              sysevent_subscribe_event(3SYSEVENT)



       #include 

       static int32_t attr_int32;

       #define    CLASS1        "class1"
       #define    CLASS2        "class2"
       #define    SUBCLASS_1    "subclass_1"
       #define    SUBCLASS_2    "subclass_2"
       #define    SUBCLASS_3    "subclass_3"
       #define    MAX_SUBCLASS  3

       static void
       event_handler(sysevent_t *ev)
       {
           nvlist_t *nvlist;

           /*
            * Special processing  for events (CLASS1, SUBCLASS_1) and
            * (CLASS2, SUBCLASS_3)
            */
           if ((strcmp(CLASS1, sysevent_get_class_name(ev)) == 0 &&
               strcmp(SUBCLASS_1, sysevent_get_subclass_name(ev)) == 0) ||
               (strcmp(CLASS2, sysevent_get_subclass_name(ev) == 0) &&
               strcmp(SUBCLASS_3, sysevent_get_subclass(ev)) == 0)) {
               if (sysevent_get_attr_list(ev, &nvlist) != 0)
                   return;
               if (nvlist_lookup_int32(nvlist, "my_int32_attr", &attr_int32)
                   != 0)
                   return;

               /* Event Processing */
           } else {
               /* Event Processing */
           }

       }


       int
       main(int argc, char **argv)
       {
           sysevent_handle_t *shp;
           const char *subclass_list[MAX_SUBCLASS];

           /* Bind event handler and create subscriber handle */
           shp = sysevent_bind_handle(event_handler);
           if (shp == NULL)
               exit(1);

           /* Subscribe to all CLASS1 event notifications */
           subclass_list[0] = EC_SUB_ALL;



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System Event Library Functions
                              sysevent_subscribe_event(3SYSEVENT)



           if (sysevent_subscribe_event(shp, CLASS1, subclass_list, 1) != 0) {
               sysevent_unbind_handle(shp);
               exit(1);
           }

           /* Subscribe to CLASS2 events for subclasses: SUBCLASS_1,
            * SUBCLASS_2 and SUBCLASS_3
            */
           subclass_list[0] = SUBCLASS_1;
           subclass_list[1] = SUBCLASS_2;
           subclass_list[2] = SUBCLASS_3;
           if (sysevent_subscribe_event(shp, CLASS2, subclass_list,
               MAX_SUBCLASS) != 0) {
               sysevent_unbind_handle(shp);
               exit(1);
           }

           for (;;) {
               (void) pause();
           }
       }


ATTRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     ____________________________________________________________
    |       ATTRIBUTE TYPE        |       ATTRIBUTE VALUE       |
    |_____________________________|_____________________________|
    | Interface Stability         | Committed                   |
    |_____________________________|_____________________________|
    | MT-Level                    | MT-Safe                     |
    |_____________________________|_____________________________|


SEE ALSO
     syseventd(1M),              sysevent_bind_handle(3SYSEVENT),
     sysevent_get_attr_list(3SYSEVENT),
     sysevent_get_class_name(3SYSEVENT),
     sysevent_get_vendor_name(3SYSEVENT), attributes(5)

NOTES
     The libsysevent interfaces do not work at all in  non-global
     zones.







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System Event Library Functions
                              sysevent_subscribe_event(3SYSEVENT)






















































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