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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | HISTORY | SEE ALSO | COLOPHON |
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SD_BUS_IS_OPEN(3) sd_bus_is_open SD_BUS_IS_OPEN(3)
sd_bus_is_open, sd_bus_is_ready - Check whether the bus connection
is open or ready
#include <systemd/sd-bus.h>
int sd_bus_is_open(sd_bus *bus);
int sd_bus_is_ready(sd_bus *bus);
sd_bus_is_open() checks whether the specified bus connection is
open, i.e. in the process of being established, already
established or in the process of being torn down. It returns zero
when the connection has not been started yet (i.e.
sd_bus_start(3) or some equivalent call has not been invoked yet),
or is fully terminated again (for example after sd_bus_close(3)),
it returns positive otherwise.
sd_bus_is_ready() checks whether the specified connection is fully
established, i.e. completed the connection and authentication
phases of the protocol and received the Hello() method call
response, and is not in the process of being torn down again. It
returns zero outside of this state, and positive otherwise.
Effectively, this function returns positive while regular messages
can be sent or received on the connection.
The bus argument may be NULL, zero is also returned in that case.
To be notified when the connection is fully established, use
sd_bus_set_connected_signal(3) and install a match for the
Connected() signal on the "org.freedesktop.DBus.Local" interface.
To be notified when the connection is torn down again, install a
match for the Disconnected() signal on the
"org.freedesktop.DBus.Local" interface.
Those functions return 0 if the bus is not in the given state, and
a positive integer when it is. On failure, a negative errno-style
error code is returned.
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_is_open() was added in version 221.
sd_bus_is_ready() was added in version 237.
systemd(1), sd-bus(3), sd_bus_start(3), sd_bus_close(3),
sd_bus_set_connected_signal(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_IS_OPEN(3)
Pages that refer to this page: sd-bus(3), sd_bus_set_connected_signal(3), sd_bus_set_watch_bind(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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