1sysevent_subscribe_event(S3ySsYtSeEmVEENvTe)nt LibrarysyFsuenvcetnito_nssubscribe_event(3SYSEVENT)
2
6 sysevent_subscribe_event, sysevent_unsubscribe_event - register or
7 unregister interest in event receipt
8
10 cc [ flag... ] file... -lsysevent [ library... ]
11 #include <libsysevent.h>
12 int sysevent_subscribe_event(sysevent_handle_t *sysevent_hdl,
14 char *event_class, char **event_subclass_list,
15 int num_subclasses);
16 void sysevent_unsubscribe_event(sysevent_handle_t *sysevent_hdl,
19 char *event_class);
20
23 event_class system event class string
24 event_subclass_list array of subclass strings
27 num_subclasses number of subclass strings
30 sysevent_hdl sysevent subscriber handle
33
36 The sysevent_subscribe_event() function registers the caller's interest
37 in event notifications belonging to the class event_class and the sub‐
38 classes contained in event_subclass_list. The subscriber handle sysev‐
39 ent_hdl is updated with the new subscription and the calling process
40 receives event notifications from the event handler specified in sysev‐
41 ent_bind_handle.
42 System events matching event_class and a subclass contained in
45 event_subclass_list published after the caller returns from sysev‐
46 ent_subscribe_event() are guaranteed to be delivered to the calling
47 process. Matching system events published and queued prior to a call
48 to sysevent_subscribe_event() may be delivered to the process's event
49 handler.
50 The num_subclasses argument provides the number of subclass string ele‐
53 ments in event_subclass_list.
54 A caller can use the event class EC_ALL to subscribe to all event
57 classes and subclasses. The event class EC_SUB_ALL can be used to sub‐
58 scribe to all subclasses within a given event class.
59 Subsequent calls to sysevent_subscribe_event() are allowed to add addi‐
62 tional classes or subclasses. To remove an existing subscription,
63 sysevent_unsubscribe_event() must be used to remove the subscription.
64 The sysevent_unsubscribe_event() function removes the subscription
67 described by event_class for sysevent_hdl. Event notifications match‐
68 ing event_class will not be delivered to the calling process upon
69 return.
70 A caller can use the event class EC_ALL to remove all subscriptions for
73 sysevent_hdl.
74 The library manages all subscription resources.
77
79 The sysevent_subscribe_event() function returns 0 if the subscription
80 is successful. Otherwise, −1 is returned and errno is set to indicate
81 the error.
82 The sysevent_unsubscribe_event() function returns no value.
85
87 The sysevent_subscribe_event() function will fail if:
88 EACCES The calling process has an ID other than the privileged user.
90 EINVAL The sysevent_hdl argument is an invalid sysevent handle.
93 ENOMEM There is insufficient memory available to allocate subscrip‐
96 tion resources.
97
100 Example 1 Subscribing for environmental events
101 #include <libsysevent.h>
103 #include <sys/nvpair.h>
104 static int32_t attr_int32;
106 #define CLASS1 "class1"
108 #define CLASS2 "class2"
109 #define SUBCLASS_1 "subclass_1"
110 #define SUBCLASS_2 "subclass_2"
111 #define SUBCLASS_3 "subclass_3"
112 #define MAX_SUBCLASS 3
113 static void
115 event_handler(sysevent_t *ev)
116 {
117 nvlist_t *nvlist;
118 /*
120 * Special processing for events (CLASS1, SUBCLASS_1) and
121 * (CLASS2, SUBCLASS_3)
122 */
123 if ((strcmp(CLASS1, sysevent_get_class_name(ev)) == 0 &&
124 strcmp(SUBCLASS_1, sysevent_get_subclass_name(ev)) == 0) ||
125 (strcmp(CLASS2, sysevent_get_subclass_name(ev) == 0) &&
126 strcmp(SUBCLASS_3, sysevent_get_subclass(ev)) == 0)) {
127 if (sysevent_get_attr_list(ev, &nvlist) != 0)
128 return;
129 if (nvlist_lookup_int32(nvlist, "my_int32_attr", &attr_int32)
130 != 0)
131 return;
132 /* Event Processing */
134 } else {
135 /* Event Processing */
136 }
137 }
139 int
142 main(int argc, char **argv)
143 {
144 sysevent_handle_t *shp;
145 const char *subclass_list[MAX_SUBCLASS];
146 /* Bind event handler and create subscriber handle */
148 shp = sysevent_bind_handle(event_handler);
149 if (shp == NULL)
150 exit(1);
151 /* Subscribe to all CLASS1 event notifications */
153 subclass_list[0] = EC_SUB_ALL;
154 if (sysevent_subscribe_event(shp, CLASS1, subclass_list, 1) != 0) {
155 sysevent_unbind_handle(shp);
156 exit(1);
157 }
158 /* Subscribe to CLASS2 events for subclasses: SUBCLASS_1,
160 * SUBCLASS_2 and SUBCLASS_3
161 */
162 subclass_list[0] = SUBCLASS_1;
163 subclass_list[1] = SUBCLASS_2;
164 subclass_list[2] = SUBCLASS_3;
165 if (sysevent_subscribe_event(shp, CLASS2, subclass_list,
166 MAX_SUBCLASS) != 0) {
167 sysevent_unbind_handle(shp);
168 exit(1);
169 }
170 for (;;) {
172 (void) pause();
173 }
174 }
175
178 See attributes(5) for descriptions of the following attributes:
179 ┌─────────────────────────────┬─────────────────────────────┐
184 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
185 ├─────────────────────────────┼─────────────────────────────┤
186 │Interface Stability │Committed │
187 ├─────────────────────────────┼─────────────────────────────┤
188 │MT-Level │MT-Safe │
189 └─────────────────────────────┴─────────────────────────────┘
190
192 syseventd(1M), sysevent_bind_handle(3SYSEVENT), sysev‐
193 ent_get_attr_list(3SYSEVENT), sysevent_get_class_name(3SYSEVENT),
194 sysevent_get_vendor_name(3SYSEVENT), attributes(5)
195
197 The libsysevent interfaces do not work at all in non-global zones.
198SunOS 5.11 24 Jul 200s9ysevent_subscribe_event(3SYSEVENT)