sd_bus_request_name(3) — Linux manual page

NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | SEE ALSO | COLOPHON

SD_BUS_REQUEST_NAME(3)     sd_bus_request_name    SD_BUS_REQUEST_NAME(3)

NAME         top

       sd_bus_request_name, sd_bus_request_name_async,
       sd_bus_release_name, sd_bus_release_name_async - Request or
       release a well-known service name on a bus

SYNOPSIS         top

       #include <systemd/sd-bus.h>

       typedef int (*sd_bus_message_handler_t)(sd_bus_message *m,
                                               void *userdata,
                                               sd_bus_error *ret_error);

       int sd_bus_request_name(sd_bus *bus, const char *name,
                               uint64_t flags);

       int sd_bus_request_name_async(sd_bus *bus, sd_bus_slot **slot,
                                     const char *name, uint64_t flags,
                                     sd_bus_message_handler_t callback,
                                     void *userdata);

       int sd_bus_release_name(sd_bus *bus, const char *name);

       int sd_bus_release_name_async(sd_bus *bus, sd_bus_slot **slot,
                                     const char *name,
                                     sd_bus_message_handler_t callback,
                                     void *userdata);

DESCRIPTION         top

       sd_bus_request_name() requests a well-known service name on a
       bus. It takes a bus connection, a valid bus name, and a flags
       parameter. The flags parameter is a combination of zero or more
       of the following flags:

       SD_BUS_NAME_ALLOW_REPLACEMENT
           After acquiring the name successfully, 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 the name if it was already acquired by another
           peer, and that other peer has permitted takeover by setting
           SD_BUS_NAME_ALLOW_REPLACEMENT while acquiring it.

       SD_BUS_NAME_QUEUE
           Queue the acquisition of the name when the name is already
           taken.

       sd_bus_request_name() operates in a synchronous fashion: a
       message requesting the name is sent to the bus broker, and the
       call waits until the broker responds.

       sd_bus_request_name_async() is an asynchronous version of
       sd_bus_request_name(). Instead of waiting for the request to
       complete, the request message is enqueued. The specified callback
       will be called when the broker's response is received. If the
       parameter is specified as NULL a default implementation is used
       instead which will terminate the connection when the name cannot
       be acquired. The function returns a slot object in its slot
       parameter — if it is passed as non-NULL — which may be used as a
       reference to the name request operation. Use sd_bus_slot_unref(3)
       to destroy this reference. Note that destroying the reference
       will not unregister the name, but simply ensure the specified
       callback is no longer called.

       sd_bus_release_name() releases an acquired well-known name. It
       takes a bus connection and a valid bus name as parameters. This
       function operates synchronously, sending a release request
       message to the bus broker and waiting for it to reply.

       sd_bus_release_name_async() is an asynchronous version of
       sd_bus_release_name(). The specified callback function is called
       when the name has been released successfully. If specified as
       NULL a generic implementation is used that ignores the result of
       the operation. As above, the slot (if non-NULL) is set to an
       object that may be used to reference the operation.

       These functions are supported only on bus connections, i.e.
       connections to a bus broker and not on direct connections.

RETURN VALUE         top

       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.

       -ESRCH
           It was attempted to release a name that is currently not
           registered on the bus.

       -EADDRINUSE
           It was attempted to release a name that is owned by a
           different peer on the bus.

       -EINVAL
           A specified parameter is invalid. This is also generated when
           the requested name is a special service name reserved by the
           D-Bus specification, or when the operation is requested on a
           connection that does not refer to a bus.

       -ENOTCONN
           The bus connection has been disconnected.

       -ECHILD
           The bus connection has been created in a different process
           than the current one.

NOTES         top

       These APIs are implemented as a shared library, which can be
       compiled and linked to with the libsystemd pkg-config(1) file.

SEE ALSO         top

       systemd(1), sd-bus(3), sd_bus_new(3), sd_bus_slot_unref(3)

COLOPHON         top

       This page is part of the systemd (systemd system and service
       manager) project.  Information about the project can be found at
       ⟨http://www.freedesktop.org/wiki/Software/systemd⟩.  If you have
       a bug report for this manual page, see
       ⟨http://www.freedesktop.org/wiki/Software/systemd/#bugreports⟩.
       This page was obtained from the project's upstream Git repository
       ⟨https://github.com/systemd/systemd.git⟩ on 2021-06-20.  (At that
       time, the date of the most recent commit that was found in the
       repository was 2021-06-19.)  If you discover any rendering
       problems in this HTML version of the page, or you believe there
       is a better or more up-to-date source for the page, or you have
       corrections or improvements to the information in this COLOPHON
       (which is not part of the original manual page), send a mail to
       man-pages@man7.org

systemd 249                                       SD_BUS_REQUEST_NAME(3)

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