| SD_BUS_IS_OPEN(3) | sd_bus_is_open | SD_BUS_IS_OPEN(3) |
.SH "NAME" sd_bus_is_open, sd_bus_is_ready - Check whether the bus
connection is open or ready
.SH "SYNOPSIS"
#include <systemd/sd-bus.h>
.HP 456u int sd_bus_is_open(sd_bus *bus);
.HP 480u int sd_bus_is_ready(sd_bus *bus);
.SH "DESCRIPTION"
.PP 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.
.PP 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.
.PP The bus argument may be NULL, zero is also returned in that
case.
.PP 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.
.SH "RETURN VALUE"
.PP 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.
.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_is_open() was added in version 221.
.PP sd_bus_is_ready() was added in version 237.
.SH "SEE ALSO"
.PP systemd(1), sd-bus(3), sd_bus_start(3),
sd_bus_close(3), sd_bus_set_connected_signal(3)
| systemd 262.2 |