sd_event_source_get_userdata(3) — Linux manual page



NAME         top

       sd_event_source_set_userdata, sd_event_source_get_userdata - Set or
       retrieve user data pointer of event sources

SYNOPSIS         top

       #include <systemd/sd-event.h>

       void* sd_event_source_set_userdata(sd_event_source *source,
                                          void *userdata);

       void* sd_event_source_get_userdata(sd_event_source *source);

DESCRIPTION         top

       sd_event_source_set_userdata() may be used to set an arbitrary user
       data pointer for the event source object specified as source. The
       user data pointer is usually specified when creating an event source
       object with calls such as sd_event_add_io(3) or sd_event_add_time(3),
       and may be updated with this call. The user data pointer is also
       passed to all handler callback functions associated with the event
       source. The userdata parameter specifies the new user data pointer to
       set, the function returns the previous user data pointer. Note that
       NULL is a valid user data pointer.

       sd_event_source_get_userdata() may be used to query the current user
       data pointer assigned to the event source object source.

RETURN VALUE         top

       On success, sd_event_source_set_userdata() and
       sd_event_source_get_userdata() return the previously set user data
       pointer. On failure, they return NULL.

NOTES         top

       These APIs are implemented as a shared library, which can be compiled
       and linked to with the libsystemd pkg-config(1) file.

SEE ALSO         top

       sd-event(3), sd_event_add_io(3), sd_event_add_time(3),
       sd_event_add_signal(3), sd_event_add_child(3),
       sd_event_add_inotify(3), sd_event_add_defer(3),

COLOPHON         top

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systemd 246                                  SD_EVENT_SOURCE_SET_USERDATA(3)

Pages that refer to this page: 30-systemd-environment-d-generator(7)systemd.index(7)