|
NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | SEE ALSO | COLOPHON |
SD_BUS_SLOT_SET_DESTROY_CALLBACK(3)et_destroy_callbackET_DESTROY_CALLBACK(3)
sd_bus_slot_set_destroy_callback, sd_bus_slot_get_destroy_callback,
sd_bus_track_set_destroy_callback, sd_bus_track_get_destroy_callback,
sd_bus_destroy_t - Define the callback function for resource cleanup
#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);
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).
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 code.
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.
Errors
Returned errors may indicate the following problems:
-EINVAL
The slot or track parameter is NULL.
These APIs are implemented as a shared library, which can be compiled
and linked to with the libsystemd pkg-config(1) file.
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)
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project. Information about the project can be found at
⟨http://www.freedesktop.org/wiki/Software/systemd⟩. If you have a bug
report for this manual page, see
⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩. This
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systemd 246 SD_BUS_SLOT_SET_DESTROY_CALLBACK(3)
Pages that refer to this page: 30-systemd-environment-d-generator(7) , systemd.index(7)