1SD_EVENT_SOURCE_UNREF(3)     sd_event_source_unref    SD_EVENT_SOURCE_UNREF(3)
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NAME

6       sd_event_source_unref, sd_event_source_unrefp, sd_event_source_ref,
7       sd_event_source_disable_unref, sd_event_source_disable_unrefp -
8       Increase or decrease event source reference counters
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SYNOPSIS

11       #include <systemd/sd-event.h>
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13       sd_event_source* sd_event_source_unref(sd_event_source *source);
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15       void sd_event_source_unrefp(sd_event_source **source);
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17       sd_event_source* sd_event_source_ref(sd_event_source *source);
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19       sd_event_source*
20                                                      sd_event_source_disable_unref(sd_event_source *source);
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22       void sd_event_source_disable_unrefp(sd_event_source **source);
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DESCRIPTION

25       sd_event_source_unref() may be used to decrement by one the reference
26       counter of the event source object specified as source. The reference
27       counter is initially set to one, when the event source is created with
28       calls such as sd_event_add_io(3) or sd_event_add_time(3). When the
29       reference counter reaches zero it is removed from its event loop object
30       and destroyed.
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32       sd_event_source_unrefp() is similar to sd_event_source_unref() but
33       takes a pointer to a pointer to an sd_event_source object. This call is
34       useful in conjunction with GCC's and LLVM's Clean-up Variable
35       Attribute[1]. Note that this function is defined as inline function.
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37       sd_event_source_ref() may be used to increase by one the reference
38       counter of the event source object specified as source.
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40       sd_event_source_unref(), sd_bus_creds_unrefp() and sd_bus_creds_ref()
41       execute no operation if the passed event source object is NULL.
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43       Note that event source objects stay alive and may be dispatched as long
44       as they have a reference counter greater than zero. In order to drop a
45       reference of an event source and make sure the associated event source
46       handler function is not called anymore it is recommended to combine a
47       call of sd_event_source_unref() with a prior call to
48       sd_event_source_set_enabled() with SD_EVENT_OFF or call
49       sd_event_source_disable_unref(), see below.
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51       sd_event_source_disable_unref() combines a call to
52       sd_event_source_set_enabled() with SD_EVENT_OFF with
53       sd_event_source_unref(). This ensures that the source is disabled
54       before the local reference to it is lost. The source parameter is
55       allowed to be NULL.
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57       sd_event_source_disable_unrefp() is similar to
58       sd_event_source_unrefp(), but in addition disables the source first.
59       This call is useful in conjunction with GCC's and LLVM's Clean-up
60       Variable Attribute[1]. Note that this function is defined as inline
61       function.
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RETURN VALUE

64       sd_event_source_unref() and sd_event_source_disable_unref() always
65       return NULL.  sd_event_source_ref() always returns the event source
66       object passed in.
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NOTES

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

73       sd-event(3), sd_event_add_io(3), sd_event_add_time(3),
74       sd_event_add_signal(3), sd_event_add_child(3), sd_event_add_inotify(3),
75       sd_event_add_defer(3), sd_event_source_set_enabled(3)
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NOTES

78        1. Clean-up Variable Attribute
79           https://gcc.gnu.org/onlinedocs/gcc/Common-Variable-Attributes.html
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83systemd 248                                           SD_EVENT_SOURCE_UNREF(3)
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