sd_bus_slot_set_destroy_callback(3) — Linux manual page



NAME         top

       sd_bus_track_get_destroy_callback, sd_bus_destroy_t - Define the
       callback function for resource cleanup

SYNOPSIS         top

       #include <systemd/sd-bus.h>

       typedef int (*sd_bus_destroy_t)(void *userdata);

       int sd_bus_slot_set_destroy_callback(sd_bus_slot *slot,
                                            sd_bus_destroy_t callback);

       int sd_bus_slot_get_destroy_callback(sd_bus_slot *slot,
                                            sd_bus_destroy_t *callback);

       int sd_bus_track_set_destroy_callback(sd_bus_track *track,
                                             sd_bus_destroy_t callback);

       int sd_bus_track_get_destroy_callback(sd_bus_track *track,
                                             sd_bus_destroy_t *callback);

DESCRIPTION         top

       sd_bus_slot_set_destroy_callback() sets callback as the callback
       function to be called right before the bus slot object slot is
       deallocated. The userdata pointer from the slot object will be
       passed as the userdata parameter. This pointer can be set by an
       argument to the constructor functions, see sd_bus_add_match(3),
       or directly, see sd_bus_slot_set_userdata(3). This callback
       function is called even if userdata is NULL. Note that this
       callback is invoked at a time where the bus slot object itself is
       already invalidated, and executing operations or taking new
       references to the bus slot object is not permissible.

       sd_bus_slot_get_destroy_callback() returns the current callback
       for slot in the callback parameter.

       sd_bus_track_set_destroy_callback() and
       sd_bus_track_get_destroy_callback() provide equivalent
       functionality for the userdata pointer associated with bus peer
       tracking objects. For details about bus peer tracking objects,
       see sd_bus_track_new(3).

RETURN VALUE         top

       On success, sd_bus_slot_set_destroy_callback() and
       sd_bus_track_set_destroy_callback() return 0 or a positive
       integer. On failure, they return a negative errno-style error

       sd_bus_slot_get_destroy_callback() and
       sd_bus_track_get_destroy_callback() return positive if the
       destroy callback function is set, 0 if not. On failure, they
       return a negative errno-style error code.

       Returned errors may indicate the following problems:

           The slot or track parameter is 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

       systemd(1), sd-bus(3), sd_bus_slot_set_floating(3),
       sd_bus_add_match(3), sd_bus_track_new(3),
       sd_bus_slot_set_userdata(3), sd_bus_track_set_userdata(3)

COLOPHON         top

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       This page was obtained from the project's upstream Git repository
       ⟨⟩ on 2021-08-27.  (At that
       time, the date of the most recent commit that was found in the
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systemd 249                          SD_BUS_SLOT_SET_DESTROY_CALLBACK(3)

Pages that refer to this page: sd-bus(3)sd_bus_slot_set_floating(3)sd_bus_slot_set_userdata(3)