1SD_EVENT_SOURCE_SET_USERDAsTdA_(e3v)ent_source_set_useSrDd_aEtVaENT_SOURCE_SET_USERDATA(3)
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6 sd_event_source_set_userdata, sd_event_source_get_userdata - Set or
7 retrieve user data pointer of event sources
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10 #include <systemd/sd-event.h>
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12 void* sd_event_source_set_userdata(sd_event_source *source,
13 void *userdata);
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15 void* sd_event_source_get_userdata(sd_event_source *source);
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18 sd_event_source_set_userdata() may be used to set an arbitrary user
19 data pointer for the event source object specified as source. The user
20 data pointer is usually specified when creating an event source object
21 with calls such as sd_event_add_io(3) or sd_event_add_time(3), and may
22 be updated with this call. The user data pointer is also passed to all
23 handler callback functions associated with the event source. The
24 userdata parameter specifies the new user data pointer to set, the
25 function returns the previous user data pointer. Note that NULL is a
26 valid user data pointer.
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28 sd_event_source_get_userdata() may be used to query the current user
29 data pointer assigned to the event source object source.
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32 On success, sd_event_source_set_userdata() and
33 sd_event_source_get_userdata() return the previously set user data
34 pointer. On failure, they return NULL.
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37 These APIs are implemented as a shared library, which can be compiled
38 and linked to with the libsystemd pkg-config(1) file.
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41 sd-event(3), sd_event_add_io(3), sd_event_add_time(3),
42 sd_event_add_signal(3), sd_event_add_child(3), sd_event_add_inotify(3),
43 sd_event_add_defer(3), sd_event_source_set_description(3)
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47systemd 241 SD_EVENT_SOURCE_SET_USERDATA(3)