NAME

zmq_msg_init_data - initialise 0MQ message from a supplied buffer

SYNOPSIS

typedef void (zmq_free_fn) (void '*data', void '*hint');

int zmq_msg_init_data (zmq_msg_t '*msg', void '*data', size_t 'size', zmq_free_fn '*ffn', void '*hint');

DESCRIPTION

The zmq_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 0MQ 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 0MQ, with the 'data' and 'hint' arguments supplied to zmq_msg_init_data().

Caution
Never access 'zmq_msg_t' members directly, instead always use the zmq_msg family of functions.
Caution
The deallocation function 'ffn' needs to be thread-safe, since it will be called from an arbitrary thread.
Caution
If the deallocation function is not provided, the allocated memory will not be freed, and this may cause a memory leak.
Caution
The functions zmq_msg_init(), zmq_msg_init_data(), zmq_msg_init_size() and zmq_msg_init_buffer() are mutually exclusive. Never initialise the same 'zmq_msg_t' twice.

RETURN VALUE

The zmq_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);
zmq_msg_t msg;
rc = zmq_msg_init_data (&msg, data, 6, my_free, NULL);
assert (rc == 0);

SEE ALSO

AUTHORS

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