sd_bus_is_open(3) — Linux manual page

SD_BUS_IS_OPEN(3)            sd_bus_is_open            SD_BUS_IS_OPEN(3)

NAME

       sd_bus_is_open, sd_bus_is_ready - Check whether the bus
       connection is open or ready

SYNOPSIS

       #include <systemd/sd-bus.h>

       int sd_bus_is_open(sd_bus *bus);

       int sd_bus_is_ready(sd_bus *bus);

DESCRIPTION

       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.

RETURN VALUE

       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.

NOTES

       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.

HISTORY

       sd_bus_is_open() was added in version 221.

       sd_bus_is_ready() was added in version 237.

SEE ALSO

       systemd(1), sd-bus(3), sd_bus_start(3), sd_bus_close(3),
       sd_bus_set_connected_signal(3)

COLOPHON

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       ⟨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
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systemd 257~devel                                      SD_BUS_IS_OPEN(3)

Pages that refer to this page: sd_bus_set_connected_signal(3), sd_bus_set_watch_bind(3), systemd.directives(7), systemd.index(7)

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