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NAME |SYNOPSIS |DESCRIPTION |RETURN VALUE |NOTES |HISTORY |SEE ALSO |COLOPHON | |
SD_BUS_START(3) sd_bus_startSD_BUS_START(3)sd_bus_start - Initiate a bus connection to the D-bus broker daemon
#include <systemd/sd-bus.h>int sd_bus_start(sd_bus *bus);
sd_bus_start()connects an existing bus connection object to the D-Bus broker daemon, usuallydbus-daemon(1) ordbus-broker(1). The mechanism to use for the connection must be configured before the call tosd_bus_start(), using one ofsd_bus_set_address(3),sd_bus_set_fd(3), orsd_bus_set_exec(3).sd_bus_start()will open the connection socket or spawn the executable as needed, and asynchronously start aorg.freedesktop.DBus.Hello()call. The answer to the Hello call will be processed later fromsd_bus_process(3). If opening of the connection or queuing of the asynchronous call fail, the connection will be closed withsd_bus_close(3). In most cases, it is better to usesd_bus_default_user(3),sd_bus_default_system(3) or related calls instead of the more low-levelsd_bus_new()andsd_bus_start(). The higher-level functions not only allocate a bus object but also start the connection to a well-known bus in a single function call.
On success, this function returns a non-negative integer. On failure, it returns a negative errno-style error code.Errors-EINVAL The input parameterbus isNULL. Added in version 246.-ENOPKG Bus objectbus could not be resolved. Added in version 246.-EPERM The input parameterbus is in a wrong state (sd_bus_start() may only be called once on a newly-created bus object). Added in version 246.-ECHILD The bus objectbus was created in a different process. Added in version 246. In addition, other connection-related errors may be returned. Seesd_bus_send(3).
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_start()was added in version 246.
systemd(1),sd-bus(3),sd_bus_default(3),sd_bus_call_async(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_START(3)Pages that refer to this page:sd-bus(3), sd_bus_default(3), sd_bus_is_open(3), sd_bus_negotiate_fds(3), sd_bus_new(3), sd_bus_set_address(3), sd_bus_set_fd(3), sd_bus_set_server(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. | |