| SD_BUS_SET_CONNECTED_SIGNAL(3) | sd_bus_set_connected_signal | SD_BUS_SET_CONNECTED_SIGNAL(3) |
.SH "NAME" sd_bus_set_connected_signal, sd_bus_get_connected_signal
- Control emission of local connection establishment signal on bus
connections
.SH "SYNOPSIS"
#include <systemd/sd-bus.h>
.HP 768u int sd_bus_set_connected_signal(sd_bus *bus,
int b);
.HP 768u int
sd_bus_get_connected_signal(sd_bus *bus);
.SH "DESCRIPTION"
.PP 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.
.PP sd_bus_get_connected_signal() may be used to query whether this
feature is enabled. It returns zero if not, positive otherwise.
.PP 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.
.PP 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.
.PP 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().
.SH "RETURN VALUE"
.PP On success, these functions return 0 or a positive integer. On failure,
they return a negative errno-style error code.
.SS "Errors"
.PP Returned errors may indicate the following problems:
.PP -ECHILD
The bus connection has been created in a different process, library or module
instance.
.RE
.SH "NOTES"
.PP Functions described here are available as a shared library, which can be
compiled against and linked to with the
libsystemd pkg-config(1) file.
.PP All functions listed here are thread-agnostic and only a single thread
may operate on a given object at any given time. Different threads may
access the same object at different times. Multiple independent objects may
be used from different threads in parallel.
.PP 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.
.SH "HISTORY"
.PP sd_bus_set_connected_signal() and
sd_bus_get_connected_signal() were added in version 237.
.SH "SEE ALSO"
.PP systemd(1), sd-bus(3), sd_bus_match_signal_async(3),
sd_bus_set_watch_bind(3), sd_bus_is_ready(3)
| systemd 262.2 |