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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | HISTORY | SEE ALSO | COLOPHON |
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SD_BUS_CLOSE(3) sd_bus_close SD_BUS_CLOSE(3)
sd_bus_close, sd_bus_flush, sd_bus_default_flush_close - Close and
flush a bus connection
#include <systemd/sd-bus.h>
void sd_bus_close(sd_bus *bus);
int sd_bus_flush(sd_bus *bus);
void sd_bus_default_flush_close(void);
sd_bus_close() disconnects the specified bus connection. When this
call is invoked and the specified bus object refers to an active
connection it is immediately terminated. No further messages may
be sent or received on it. Any messages queued in the bus object
(both incoming and outgoing) are released. If invoked on NULL bus
object or when the bus connection is already closed this function
executes no operation. This call does not free or unreference the
bus object itself. Use sd_bus_unref(3) for that.
sd_bus_flush() synchronously writes out all outgoing queued
message on a bus connection if there are any. This function call
may block if the peer is not processing bus messages quickly.
Before a program exits it is usually a good idea to flush any
pending messages with sd_bus_flush() and then close connections
with sd_bus_close() to ensure that no unwritten messages are lost,
no further messages may be queued and all incoming but unprocessed
messages are released. After both operations have been done, it is
a good idea to also drop any remaining references to the bus
object so that it may be freed. Since these three operations are
frequently done together a helper call sd_bus_flush_close_unref(3)
is provided that combines them into one.
sd_bus_default_flush_close() is similar to
sd_bus_flush_close_unref(), but does not take a bus pointer
argument and instead iterates over any of the "default" buses
opened by sd_bus_default(3), sd_bus_default_user(3),
sd_bus_default_system(3), and similar calls.
sd_bus_default_flush_close() is particularly useful to clean up
any buses opened using those calls before the program exits.
On success, sd_bus_flush() returns a non-negative integer. On
failure, it returns a negative errno-style error code.
Errors
Returned errors may indicate the following problems:
-ECHILD
The bus connection has been created in a different process,
library or module instance.
Functions described here are available as a shared library, which
can be compiled against and linked to with the
libsystemd pkg-config(1) file.
The code described here uses getenv(3), which is declared to be
not multi-thread-safe. This means that the code calling the
functions described here must not call setenv(3) from a parallel
thread. It is recommended to only do calls to setenv() from an
early phase of the program when no other threads have been
started.
sd_bus_close() and sd_bus_flush() were added in version 221.
sd_bus_default_flush_close() was added in version 227.
systemd(1), sd-bus(3), sd_bus_unref(3),
sd_bus_set_close_on_exit(3)
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 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 is not part of the original manual page), send a mail to
man-pages@man7.org
systemd 258~rc2 SD_BUS_CLOSE(3)
Pages that refer to this page: sd-bus(3), sd_bus_default(3), sd_bus_get_n_queued_read(3), sd_bus_is_open(3), sd_bus_new(3), sd_bus_set_close_on_exit(3), sd_bus_start(3), systemd.directives(7), systemd.index(7)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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