sd_bus_request_name
systemd
Developer
Lennart
Poettering
lennart@poettering.net
sd_bus_request_name
3
sd_bus_request_name
sd_bus_release_name
Request or release a well-known name on a bus
#include <systemd/sd-bus.h>
int sd_bus_request_name
sd_bus* bus
const char *name
unsigned flags
int sd_bus_release_name
sd_bus* bus
const char *name
Description
sd_bus_request_name() requests
a well-known name on a bus. It takes a bus connection,
a valid bus name and a flags parameter. The flags
parameter is a combination of the following
flags:
SD_BUS_NAME_ALLOW_REPLACEMENT
After acquiring the
name successuflly, permit other peers
to take over the name when they try to
acquire it with the
SD_BUS_NAME_REPLACE_EXISTING
flag set. If
SD_BUS_NAME_ALLOW_REPLACEMENT
is not set on the original request
such a request by other peers will be
denied.
SD_BUS_NAME_REPLACE_EXISTING
Take over a the name
if it is already acquired by a another
peer, and that other peer permitted
taking it over by setting
SD_BUS_NAME_ALLOW_REPLACEMENT
while acquiring it.
SD_BUS_NAME_QUEUE
Queue name
acquisition when the name is already
taken.
sd_bus_release_name() releases
an acquired well-known name. It takes a bus connection
and a valid bus name as parameters.
Return Value
On success, these calls return 0 or a positive
integer. On failure, these calls return a negative
errno-style error code.
If SD_BUS_NAME_QUEUE is
specified sd_bus_request_name()
will return 0 when the name is already taken by
another peer and the client has been added to the
queue for the name. In that case the caller can
subscribe to NameOwnerChanged
signals to be notified when the name is successfully
acquired. sd_bus_request_name()
returns > 0 when the name has immediately been
acquired successfully.
Errors
Returned errors may indicate the following problems:
-EALREADY
The caller already is
the owner of the specified
name.
-EEXIST
The name has already
been acquired by a different peer, and
SD_BUS_NAME_REPLACE_EXISTING was not
specified or the other peer did not
specify SD_BUS_NAME_ALLOW_REPLACEMENT
while acquiring the
name.
-EINVAL
A specified parameter
is invalid.
-ENOTCONN
The bus connection has
been disconnected.
-ECHILD
The bus connection has
been created in a different process
than the current.
Notes
The sd_bus_acquire_name()
and sd_bus_release_bame()
interfaces are available as shared library, which can
be compiled and linked to with the
libsystemd-bus pkg-config1
file.
See Also
systemd1,
sd-bus3,
sd_bus_new3