mirror of
https://github.com/zeromq/libzmq.git
synced 2024-12-27 23:51:04 +08:00
90 lines
2.1 KiB
Plaintext
90 lines
2.1 KiB
Plaintext
zmq_msg_init_data(3)
|
|
====================
|
|
|
|
|
|
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()_ and
|
|
_zmq_msg_init_size()_ 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
|
|
--------
|
|
linkzmq:zmq_msg_init_size[3]
|
|
linkzmq:zmq_msg_init[3]
|
|
linkzmq:zmq_msg_close[3]
|
|
linkzmq:zmq_msg_data[3]
|
|
linkzmq:zmq_msg_size[3]
|
|
linkzmq:zmq[7]
|
|
|
|
|
|
AUTHORS
|
|
-------
|
|
This page was written by the 0MQ community. To make a change please
|
|
read the 0MQ Contribution Policy at <http://www.zeromq.org/docs:contributing>.
|