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sd_bus_slot_ref(3) — Linux manual page

SD_BUS_SLOT_REF(3)           sd_bus_slot_refSD_BUS_SLOT_REF(3)

NAME        top

       sd_bus_slot_ref, sd_bus_slot_unref, sd_bus_slot_unrefp - Create       and destroy references to a bus slot object

SYNOPSIS        top

#include <systemd/sd-bus.h>sd_bus_slot *sd_bus_slot_ref(sd_bus_slot *slot);sd_bus_slot *sd_bus_slot_unref(sd_bus_slot *slot);void sd_bus_slot_unrefp(sd_bus_slot **slotp);

DESCRIPTION        top

sd_bus_slot_ref()increases the internal reference counter ofslot       by one.sd_bus_slot_unref()decreases the internal reference counter ofslot by one. Once the reference count has dropped to zero, slot       object is destroyed and cannot be used anymore, so further calls       tosd_bus_slot_ref()orsd_bus_slot_unref()are illegal.sd_bus_slot_unrefp()is similar tosd_bus_slot_unref()but takes a       pointer to a pointer to ansd_bus_slotobject. This call is useful       in conjunction with GCC's and LLVM'sClean-up VariableAttribute[1]. Seesd_bus_new(3) for an example how to use the       cleanup attribute.sd_bus_slot_ref()andsd_bus_slot_unref()execute no operation if       the passed in bus object address isNULL.sd_bus_slot_unrefp()       will first dereference its argument, which must not beNULL, and       will execute no operation ifthat isNULL.

RETURN VALUE        top

sd_bus_slot_ref()always returns the argument.sd_bus_slot_unref()always returnsNULL.

NOTES        top

       Functions described here are available as a shared library, which       can be compiled against and linked to with thelibsystemd pkg-config(1) file.       The code described here usesgetenv(3), which is declared to be       not multi-thread-safe. This means that the code calling the       functions described here must not callsetenv(3) from a parallel       thread. It is recommended to only do calls tosetenv()from an       early phase of the program when no other threads have been       started.

HISTORY        top

sd_bus_slot_ref(),sd_bus_slot_unref(), andsd_bus_slot_unrefp()       were added in version 240.

SEE ALSO        top

systemd(1),sd-bus(3),sd_bus_new(3),sd_bus_message_new(3),sd_bus_call_method_async(3)

NOTES        top

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

COLOPHON        top

       This page is part of thesystemd (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 2025-08-11.  (At that       time, the date of the most recent commit that was found in the       repository was 2025-08-11.)  If you discover 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 isnot part of the original manual page), send a mail to       man-pages@man7.orgsystemd 258~rc2SD_BUS_SLOT_REF(3)

Pages that refer to this page:sd_bus_add_match(3), sd_bus_add_node_enumerator(3), sd_bus_add_object(3), sd_bus_add_object_manager(3), sd_bus_call(3), sd_bus_request_name(3), sd_bus_slot_set_description(3), systemd.directives(7), systemd.index(7)

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