NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | SEE ALSO | NOTES | COLOPHON

SD_EVENT_SOURCE_UNREF(3)    sd_event_source_unref   SD_EVENT_SOURCE_UNREF(3)

NAME         top

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

SYNOPSIS         top

       #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         top

       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         top

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

NOTES         top

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

SEE ALSO         top

       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         top

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

COLOPHON         top

       This page is part of the systemd (systemd system and service manager)
       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
       page was obtained from the project's upstream Git repository 
       ⟨https://github.com/systemd/systemd.git⟩ on 2017-03-13.  If you dis‐
       cover any rendering problems in this HTML version of the page, or you
       believe there is a better or more up-to-date source for the page, or
       you have corrections or improvements to the information in this
       COLOPHON (which is not part of the original manual page), send a mail
       to man-pages@man7.org

systemd 233                                         SD_EVENT_SOURCE_UNREF(3)