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. |  |
NAME |SYNOPSIS |DESCRIPTION |RETURN VALUE |NOTES |HISTORY |SEE ALSO |COLOPHON | |
SD_BUS_ATTACH_EVENT(3) sd_bus_attach_eventSD_BUS_ATTACH_EVENT(3)sd_bus_attach_event, sd_bus_detach_event, sd_bus_get_event - Attach a bus connection object to an event loop
#include <systemd/sd-bus.h>int sd_bus_attach_event(sd_bus *bus, sd_event *e, intpriority);int sd_bus_detach_event(sd_bus *bus);sd_event *sd_bus_get_event(sd_bus *bus);
sd_bus_attach_event()attaches the specified bus connection object to ansd-event(3) event loop object at the specified priority (seesd_event_source_set_priority(3) for details on event loop priorities). When a bus connection object is attached to an event loop incoming messages will be automatically read and processed, and outgoing messages written, whenever the event loop is run. When the event loop is about to terminate, the bus connection is automatically flushed and closed (seesd_bus_set_close_on_exit(3) for details on this). By default, bus connection objects are not attached to any event loop. When a bus connection object is attached to one it is not necessary to invokesd_bus_wait(3) orsd_bus_process(3) as this functionality is handled automatically by the event loop.sd_bus_detach_event()detaches a bus object from its event loop. Thesd_bus_get_event()returns the event loop object the specified bus object is currently attached to, orNULLif it is currently not attached to any. Note thatsd_bus_attach_event()is only one of three supported ways to implement I/O event handling for bus connections. Alternatively usesd_bus_get_fd(3) for hooking up a bus connection object with external or manual event loops. Or usesd_bus_wait(3) as a simple synchronous, blocking I/O waiting call.
On success,sd_bus_attach_event()andsd_bus_detach_event()return 0 or a positive integer. On failure, they return a negative errno-style error code.sd_bus_get_event()returns an event loop object orNULL.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_attach_event(),sd_bus_detach_event(), andsd_bus_get_event()were added in version 221.
systemd(1),sd-bus(3),sd-event(3),sd_event_source_set_priority(3),sd_bus_set_close_on_exit(3),sd_bus_wait(3),sd_bus_get_fd(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_ATTACH_EVENT(3)Pages that refer to this page:sd-bus(3), sd_bus_get_fd(3), sd_bus_process(3), sd_bus_set_close_on_exit(3), sd_bus_set_exit_on_disconnect(3), sd_bus_wait(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. | |