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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | HISTORY | SEE ALSO | COLOPHON |
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SD_BUS_ATTACH_EVENT(3) sd_bus_attach_event SD_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, int priority);
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 an sd-event(3) event loop object at the specified
priority (see sd_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 (see
sd_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
invoke sd_bus_wait(3) or sd_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.
The sd_bus_get_event() returns the event loop object the
specified bus object is currently attached to, or NULL if it is
currently not attached to any.
Note that sd_bus_attach_event() is only one of three supported
ways to implement I/O event handling for bus connections.
Alternatively use sd_bus_get_fd(3) for hooking up a bus
connection object with external or manual event loops. Or use
sd_bus_wait(3) as a simple synchronous, blocking I/O waiting
call.
On success, sd_bus_attach_event() and sd_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 or NULL.
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_attach_event(), sd_bus_detach_event(), and
sd_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 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 2024-06-14. (At that
time, the date of the most recent commit that was found in the
repository was 2024-06-13.) 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 257~devel SD_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)
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HTML rendering created 2024-06-26 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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