sd_event_source_unref
systemd
sd_event_source_unref
3
sd_event_source_unref
sd_event_source_unrefp
sd_event_source_ref
sd_event_source_disable_unref
sd_event_source_disable_unrefp
Increase or decrease event source reference counters
#include <systemd/sd-event.h>
sd_event_source* sd_event_source_unref
sd_event_source *source
void sd_event_source_unrefp
sd_event_source **source
sd_event_source* sd_event_source_ref
sd_event_source *source
sd_event_source* sd_event_source_disable_unref
sd_event_source *source
void sd_event_source_disable_unrefp
sd_event_source **source
Description
sd_event_source_unref() may be used to decrement by one the internal reference
counter of the event source object specified as source. The reference counter is
initially set to one, when the event source is created with calls such as
sd_event_add_io3 or
sd_event_add_time3. When
the reference counter reaches zero, the object is detached from the event loop object and destroyed.
sd_event_source_unrefp() is similar to
sd_event_source_unref() but takes a pointer to a
pointer to an sd_event_source object. This call is useful in
conjunction with GCC's and LLVM's Clean-up
Variable Attribute. Note that this function is defined as
inline function.
sd_event_source_ref() may be used to increase by one the internal reference
counter of the event source object specified as source.
sd_event_source_unref(),
sd_bus_creds_unrefp() and
sd_bus_creds_ref() execute no operation if
the passed event source object is
NULL.
Note that event source objects stay alive and may be dispatched as long as they have a reference
counter greater than zero. In order to drop a reference of an event source and make sure the associated
event source handler function is not called anymore it is recommended to combine a call of
sd_event_source_unref() with a prior call to
sd_event_source_set_enabled() with SD_EVENT_OFF or call
sd_event_source_disable_unref(), see below.
sd_event_source_disable_unref() combines a call to
sd_event_source_set_enabled() with SD_EVENT_OFF with
sd_event_source_unref(). This ensures that the source is disabled before the local
reference to it is lost. The source parameter is allowed to be
NULL.
sd_event_source_disable_unrefp() is similar to
sd_event_source_unrefp(), but in addition disables the source first. This call is
useful in conjunction with GCC's and LLVM's
Clean-up Variable
Attribute. Note that this function is defined as inline function.
Return Value
sd_event_source_unref() and
sd_event_source_disable_unref() always return NULL.
sd_event_source_ref() always returns the event source object passed in.
See Also
sd-event3,
sd_event_add_io3,
sd_event_add_time3,
sd_event_add_signal3,
sd_event_add_child3,
sd_event_add_inotify3,
sd_event_add_defer3,
sd_event_source_set_enabled3