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sd_bus_get_n_queued_read(3) — Linux manual page

SD_BUS_GET_N_QUEUED_READ(3)   sd_bus_get_fdSD_BUS_GET_N_QUEUED_READ(3)

NAME        top

       sd_bus_get_n_queued_read, sd_bus_get_n_queued_write - Get the       number of pending bus messages in the read and write queues of a       bus connection object

SYNOPSIS        top

#include <systemd/sd-bus.h>int sd_bus_get_n_queued_read(sd_bus *bus, uint64_t *ret);int sd_bus_get_n_queued_write(sd_bus *bus, uint64_t *ret);

DESCRIPTION        top

sd_bus_get_n_queued_read()may be used to query the number of bus       messages in the read queue of a bus connection object. The read       queue contains all messages read from the transport medium (e.g.       network socket) but not yet processed locally. The function       expects two arguments: the bus object to query, and a pointer to a       64-bit counter variable to write the current queue size to. Usesd_bus_process()in order to process queued messages, i.e. to       reduce the size of the read queue (as well as, in fact, the write       queue, see below).       Similarly,sd_bus_get_n_queued_write()may be used to query the       number of currently pending bus messages in the write queue of a       bus connection object. The write queue contains all messages       enqueued into the connection with a call such assd_bus_send()but       not yet written to the transport medium. The expected arguments       are similar tosd_bus_get_n_queued_read(). Here too, usesd_bus_process()to reduce the size of the write queue.       Alternatively, usesd_bus_flush()to synchronously write out any       pending bus messages until the write queue is empty.

RETURN VALUE        top

       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:-ECHILD           The bus connection was created in a different process, library           or module instance.

HISTORY        top

sd_bus_get_n_queued_read()andsd_bus_get_n_queued_write()were       added in version 238.

SEE ALSO        top

systemd(1),sd-bus(3),sd_bus_process(3),sd_bus_send(3),sd_bus_flush(3)

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_GET_N_QUEUED_READ(3)

Pages that refer to this page:sd-bus(3), systemd.directives(7), systemd.index(7)

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