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NAME |SYNOPSIS |DESCRIPTION |RETURN VALUE |NOTES |HISTORY |SEE ALSO |COLOPHON | |
SD_BUS_CLOSE(3) sd_bus_closeSD_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 onNULLbus 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. Usesd_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 withsd_bus_flush()and then close connections withsd_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 callsd_bus_flush_close_unref(3) is provided that combines them into one.sd_bus_default_flush_close()is similar tosd_bus_flush_close_unref(), but does not take a bus pointer argument and instead iterates over any of the "default" buses opened bysd_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 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_close()andsd_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 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_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)
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. | |