nbd_get_uri - construct an NBD URI for a connection

       Eric Blake

       Richard W.M. Jones

       Copyright Red Hat

       This makes a best effort attempt to construct an NBD URI which could be used to connect back to the same
       server (using nbd_connect_uri(3)).

       In some cases there is not enough information in the handle to successfully create a URI (eg. if you
       connected with nbd_connect_socket(3)).  In such cases the call returns "NULL" and further diagnostic
       information is available via nbd_get_errno(3) and nbd_get_error(3) as usual.

       Even if a URI is returned it is not guaranteed to work, and it may not be optimal.

       nbdinfo(1) --uri option is a way to access this API from shell scripts.

       On error "NULL" is returned.

       Refer to "ERROR HANDLING" in libnbd(3) for how to get further details of the error.

       The following parameters must not be NULL: "h".  For more information see "Non-NULL parameters" in
       libnbd(3).

       nbd_get_uri can be called when the handle is in the following states:

        ┌─────────────────────────────────────┬─────────────────────────┐
        │ Handle created, before connecting   │ ❌ error                │
        │ Connecting                          │ ✅ allowed              │
        │ Connecting & handshaking (opt_mode) │ ✅ allowed              │
        │ Connected to the server             │ ✅ allowed              │
        │ Connection shut down                │ ✅ allowed              │
        │ Handle dead                         │ ✅ allowed              │
        └─────────────────────────────────────┴─────────────────────────┘

       This library is free software; you can redistribute it and/or modify it under the terms of the GNU Lesser
       General Public License as published by the Free Software Foundation; either version 2 of the License, or
       (at your option) any later version.

       This library is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even
       the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General
       Public License for more details.

       You should have received a copy of the GNU Lesser General Public License along with this library; if not,
       write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

libnbd-1.22.2                                      2025-06-16                                     nbd_get_uri(3)

       nbd_get_uri - construct an NBD URI for a connection

       This call returns a string.  The caller must free the returned string to avoid a memory leak.

nbd_aio_connect_uri(3), nbd_connect_socket(3), nbd_connect_uri(3), nbd_create(3), nbd_get_errno(3),
       nbd_get_error(3), nbd_is_uri(3), nbd_supports_uri(3), libnbd(3), nbdinfo(1).

        #include <libnbd.h>

        char * nbd_get_uri (
                 struct nbd_handle *h
               );

       This function first appeared in libnbd 1.8.

       If you need to test if this function is available at compile time check if the following macro is
       defined:

        #define LIBNBD_HAVE_NBD_GET_URI 1