sd_bus_set_connected_signal(3) — Linux manual page


SD_BUS_...D_SIGNAL(3)  sd_bus_set_connected_signal SD_BUS_...D_SIGNAL(3)

NAME         top

       sd_bus_set_connected_signal, sd_bus_get_connected_signal -
       Control emission of local connection establishment signal on bus

SYNOPSIS         top

       #include <systemd/sd-bus.h>

       int sd_bus_set_connected_signal(sd_bus *bus, int b);

       int sd_bus_get_connected_signal(sd_bus *bus);

DESCRIPTION         top

       sd_bus_set_connected_signal() may be used to control whether a
       local, synthetic Connected() signal message shall be generated
       and enqueued for dispatching when the connection is fully
       established. If the b parameter is zero the message is not
       generated (the default), otherwise it is generated.

       sd_bus_get_connected_signal() may be used to query whether this
       feature is enabled. It returns zero if not, positive otherwise.

       The Connected() signal message is generated from the
       "org.freedesktop.DBus.Local" service and interface, and
       "/org/freedesktop/DBus/Local" object path. Use
       sd_bus_match_signal_async(3) to match on this signal.

       This message is particularly useful on slow transports where
       connections take a long time to be established. This is
       especially the case when sd_bus_set_watch_bind(3) is used. The
       signal is generated when the sd_bus_is_ready(3) returns positive
       for the first time.

       The Connected() signal corresponds with the Disconnected() signal
       that is synthesized locally when the connection is terminated.
       The latter is generated unconditionally however, unlike the
       former which needs to be enabled explicitly before it is
       generated, with sd_bus_set_connected_signal().

RETURN VALUE         top

       On success, these functions return 0 or a positive integer. On
       failure, they return a negative errno-style error code.

       Returned errors may indicate the following problems:

           The bus connection has been created in a different process,
           library or module instance.

NOTES         top

       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

HISTORY         top

       sd_bus_set_connected_signal() and sd_bus_get_connected_signal()
       were added in version 237.

SEE ALSO         top

       systemd(1), sd-bus(3), sd_bus_match_signal_async(3),
       sd_bus_set_watch_bind(3), sd_bus_is_ready(3)

COLOPHON         top

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       This page was obtained from the project's upstream Git repository
       ⟨⟩ on 2023-12-22.  (At that
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systemd 255                                        SD_BUS_...D_SIGNAL(3)

Pages that refer to this page: sd-bus(3)sd_bus_is_open(3)sd_bus_set_watch_bind(3)systemd.directives(7)systemd.index(7)