x SuSE Linux 13.1-RELEASE x
x SuSE Linux 13.1-RELEASEx
SD_EVENT_SOURCE_SET_Dsd_event_source_seSD_EVENT_SOURCE_SET_DESTROY_CALLBACK(3)
NAME
sd_event_source_set_destroy_callback,
sd_event_source_get_destroy_callback, sd_event_destroy_t - Define the
callback function for resource cleanup
SYNOPSIS
#include <systemd/sd-event.h>
typedef int (*sd_event_destroy_t)(void *userdata);
int sd_event_source_set_destroy_callback(sd_event_source *source,
sd_event_destroy_t callback);
int sd_event_source_get_destroy_callback(sd_event_source *source,
sd_event_destroy_t *callback);
DESCRIPTION
sd_event_source_set_destroy_callback() sets callback as the callback
function to be called right before the event source object source is
deallocated. The userdata pointer from the event source object will be
passed as the userdata parameter. This pointer can be set by an
argument to the constructor functions, see sd_event_add_io(3), or
directly, see sd_event_source_set_userdata(3). This callback function
is called even if userdata is NULL. Note that this callback is invoked
at a time where the event source object itself is already invalidated,
and executing operations or taking new references to the event source
object is not permissible.
sd_event_source_get_destroy_callback() returns the current callback for
source in the callback parameter.
RETURN VALUE
On success, sd_event_source_set_destroy_callback() returns 0 or a
positive integer. On failure, it returns a negative errno-style error
code.
sd_event_source_get_destroy_callback() returns positive if the destroy
callback function is set, 0 if not. On failure, returns a negative
errno-style error code.
Errors
Returned errors may indicate the following problems:
-EINVAL
The source parameter is NULL.
NOTES
Functions described here are available as a shared library, which can
be compiled against and linked to with the libsystemd pkg-config(1)
file.
The code described here uses getenv(3), which is declared to be not
multi-thread-safe. This means that the code calling the functions
described here must not call setenv(3) from a parallel thread. It is
recommended to only do calls to setenv() from an early phase of the
program when no other threads have been started.
SEE ALSO
systemd(1), 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), sd_event_source_set_userdata(3)
systemd 254 SD_EVENT_SOURCE_SET_DESTROY_CALLBACK(3)
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