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NAME |SYNOPSIS |DESCRIPTION |RETURN VALUE |NOTES |HISTORY |SEE ALSO |COLOPHON | |
SD_BUS_SL..._FLOATING(3) sd_bus_slot_set_floatingSD_BUS_SL..._FLOATING(3)sd_bus_slot_set_floating, sd_bus_slot_get_floating - Control whether a bus slot object is "floating"
#include <systemd/sd-bus.h>int sd_bus_slot_set_floating(sd_bus_slot *slot, intb);int sd_bus_slot_get_floating(sd_bus_slot *slot);
sd_bus_slot_set_floating()controls whether the specified bus slot objectslot shall be "floating" or not. A floating bus slot object's lifetime is bound to the lifetime of the bus object it is associated with, meaning that it remains allocated as long as the bus object itself and is freed automatically when the bus object is freed. Regular (i.e. non-floating) bus slot objects keep the bus referenced, hence the bus object remains allocated at least as long as there remains at least one referenced bus slot object around. The floating state hence controls the direction of referencing between the bus object and the bus slot objects: if floating the bus pins the bus slot, and otherwise the bus slot pins the bus objects. Usesd_bus_slot_set_floating()to switch between both modes: if theb parameter is zero, the slot object is made into a regular (non-floating) slot object, otherwise it is made into a floating slot object. Bus slot objects may be allocated with calls such assd_bus_add_match(3). If theslot of these functions is non-NULL the slot object will be of the regular kind (i.e. non-floating), otherwise it will be created floating. Withsd_bus_slot_set_floating()a bus slot object allocated as regular can be converted into a floating object and back. This is particularly useful for creating a bus slot object, then changing parameters of it, and then turning it into a floating object, whose lifecycle is managed by the bus object.sd_bus_slot_get_floating()returns the current floating state of the specified bus slot object. It returns negative on error, zero if the bus slot object is a regular (non-floating) object and positive otherwise.
On success, these functions return 0 or a positive integer. On failure, they return a negative errno-style error code.Errors Returned errors may indicate the following problems:-EINVAL Theslot parameter isNULL.-ECHILD The bus connection has been created in a different process, library or module instance.-ESTALE The bus object the specified bus slot object is associated with has already been freed, and hence no change in the floating state can be made anymore.
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.
sd_bus_slot_set_floating()andsd_bus_slot_get_floating()were added in version 239.
systemd(1),sd-bus(3),sd_bus_slot_set_destroy_callback(3),sd_bus_add_match(3)
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_SL..._FLOATING(3)Pages that refer to this page:sd-bus(3), 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_default(3), sd_bus_slot_set_destroy_callback(3), systemd.directives(7), systemd.index(7)
HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |