bionic (3) xs_msg_init_data.3.gz

NAME

       xs_msg_init_data - initialise Crossroads message from a supplied buffer

SYNOPSIS

       typedef void (xs_free_fn) (void *data, void *hint);

       int xs_msg_init_data (xs_msg_t *msg, void *data, size_t size, xs_free_fn *ffn, void *hint);

DESCRIPTION

       The xs_msg_init_data() function shall initialise the message object referenced by msg to represent the
       content referenced by the buffer located at address data, size bytes long. No copy of data shall be
       performed and the library shall take ownership of the supplied buffer.

       If provided, the deallocation function ffn shall be called once the data buffer is no longer required by
       the library, with the data and hint arguments supplied to xs_msg_init_data().

           Caution
           Never access xs_msg_t members directly, instead always use the xs_msg family of functions.

           Caution
           The deallocation function ffn needs to be thread-safe, since it will be called from an arbitrary
           thread.

           Caution
           The functions xs_msg_init(), xs_msg_init_data() and xs_msg_init_size() are mutually exclusive. Never
           initialize the same xs_msg_t twice.

RETURN VALUE

       The xs_msg_init_data() function shall return zero if successful. Otherwise it shall return -1 and set
       errno to one of the values defined below.

ERRORS

       ENOMEM
           Insufficient storage space is available.

EXAMPLE

       Initialising a message from a supplied buffer.

           void my_free (void *data, void *hint)
           {
               free (data);
           }

               /*  ...  */

           void *data = malloc (6);
           assert (data);
           memcpy (data, "ABCDEF", 6);
           xs_msg_t msg;
           rc = xs_msg_init_data (&msg, data, 6, my_free, NULL);
           assert (rc == 0);

SEE ALSO

       xs_msg_init_size(3) xs_msg_init(3) xs_msg_close(3) xs_msg_data(3) xs_msg_size(3) xs(7)

AUTHORS

       The Crossroads documentation was written by Martin Sustrik <sustrik@250bpm.com[1]> and Martin Lucina
       <martin@lucina.net[2]>.

NOTES

        1. sustrik@250bpm.com
           mailto:sustrik@250bpm.com

        2. martin@lucina.net
           mailto:martin@lucina.net