NAME

       sd_event_source_unref, sd_event_source_unrefp, sd_event_source_ref - Increase or decrease event source
       reference counters

SYNOPSIS

       #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);

DESCRIPTION

       sd_event_source_unref() may be used to decrement by one the 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_io(3) or sd_event_add_time(3). When the reference counter reaches zero it is
       removed from its 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[1]. Note that this function is defined as inline function.

       sd_event_source_ref() may be used to increase by one the 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.

RETURN VALUE

       sd_event_source_unref() always returns NULL.  sd_event_source_ref() always returns the event source
       object passed in.

NOTES

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

SEE ALSO

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

NOTES

        1. Clean-up Variable Attribute
           https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html

systemd 229                                                                             SD_EVENT_SOURCE_UNREF(3)