.TH zmq_msg_init_data 3 "" "(c)2007-2009 FastMQ Inc." "0MQ User Manuals"
.SH NAME
zmq_msg_init \- initialises 0MQ message from the given data
.SH SYNOPSIS
.nf
.B typedef void (zmq_free_fn) (void *data, void *hint);
.B int zmq_msg_init_data (zmq_msg_t *msg, void *data, size_t size, zmq_free_fn *ffn, void *hint);
.fi
.SH DESCRIPTION
Initialise a message from a supplied buffer. Message isn't copied,
instead 0MQ infrastructure takes ownership of the buffer located at address
.IR data ,
.IR size
bytes long. 
Deallocation function (
.IR ffn
) will be called once the data are not needed anymore. When using a static
constant buffer,
.IR ffn
may be NULL to prevent subsequent deallocation. If needed, additional
.IR hint
can be passed to the initialisation function. It's an opaque pointer that will
be later on passed to
.IR ffn
as a second argument.
.SH RETURN VALUE
In case of success the function returns zero. Otherwise it returns -1 and
sets
.IR errno
to the appropriate value.
.SH ERRORS
No errors are defined.
.SH EXAMPLE
.nf
void my_free (void *data, void *hint) {free (data);}

        ...

void *data = malloc (6);
assert (data);
memcpy (data, "ABCDEF", 6);
zmq_msg_t msg;
rc = zmq_msg_init_data (&msg, data, 6, my_free, NULL);
assert (rc == 0);
rc = zmq_send (s, &msg, 0);
assert (rc == 0);
.fi
.SH SEE ALSO
.BR zmq_msg_close (3)
.BR zmq_msg_init (3)
.BR zmq_msg_init_size (3)
.BR zmq_msg_data (3)
.BR zmq_msg_size (3)
.SH AUTHOR
Martin Sustrik <sustrik at 250bpm dot com>