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() and sd_bus_is_ready() were 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)