zmq_cpp.txt

zmq_cpp(7)
==========


NAME
----
zmq_cpp - interface between 0MQ and C++ applications


SYNOPSIS
--------
*#include <zmq.hpp>*

*c$$++$$* ['flags'] 'files' *-lzmq* ['libraries']


DESCRIPTION
-----------
This manual page describes how the 0MQ C++ language binding maps to the
underlying 0MQ C library functions. 

All 0MQ constants defined by _zmq.h_ are also available to the C++ language
binding.

The following classes are provided in the 'zmq' namespace:


Context
~~~~~~~
The 'context_t' class encapsulates functionality dealing with the
initialisation and termination of a 0MQ _context_.


Constructor
^^^^^^^^^^^
[verse]
*context_t::context_t(int 'io_threads')*

Maps to the _zmq_init()_ function, as described in linkzmq:zmq_init[3].

Destructor
^^^^^^^^^^
[verse]
*context_t::~context_t(void)*

Maps to the _zmq_term()_ function, as described in linkzmq:zmq_term[3].


Methods
^^^^^^^
None.


Socket
~~~~~~
The 'socket_t' class encapsulates a 0MQ socket.


Constructor
^^^^^^^^^^^
[verse]
*socket_t::socket_t(context_t '&context', int 'type')*

Maps to the _zmq_socket()_ function, as described in linkzmq:zmq_socket[3].


Destructor
^^^^^^^^^^
[verse]
*socket_t::~socket_t(void)*

Calls the _zmq_close()_ function, as described in linkzmq:zmq_close[3].


Methods
^^^^^^^
[verse]
*void socket_t::getsockopt(int 'option_name', void '*option_value', size_t
'*option_len')*

Maps to the _zmq_getsockopt()_ function, as described in
linkzmq:zmq_getsockopt[3].

[verse]
*void socket_t::setsockopt(int 'option_name', const void '*option_value', size_t
'option_len')*

Maps to the _zmq_setsockopt()_ function, as described in
linkzmq:zmq_setsockopt[3].

[verse]
*void socket_t::bind(const char '*endpoint')*

Maps to the _zmq_bind()_ function, as described in linkzmq:zmq_bind[3].

[verse]
*void socket_t::connect(const char '*endpoint')*

Maps to the _zmq_connect()_ function, as described in linkzmq:zmq_connect[3].

[verse]
*bool socket_t::send(message_t '&msg', int 'flags' = 0)*

Maps to the _zmq_send()_ function, as described in linkzmq:zmq_send[3].
Returns true if message is successfully sent, false if it is not.

[verse]
*bool socket_t::recv(message_t '*msg', int 'flags' = 0)*

Maps to the _zmq_recv()_ function, as described in linkzmq:zmq_recv[3].
Returns true if message is successfully received, false if it is not.


Message
~~~~~~~
The 'zmq::message_t' class encapsulates the 'zmq_msg_t' structure and
functions to construct, destruct and manipulate 0MQ messages.


Constructor
^^^^^^^^^^^
[verse]
*message_t::message_t(void)*
*message_t::message_t(size_t 'size')*
*message_t::message_t(void '*data', size_t 'size', free_fn '*ffn')*

These map to the _zmq_msg_init()_, _zmq_msg_init_size()_ and
_zmq_msg_init_data()_ functions, described in linkzmq:zmq_msg_init[3],
linkzmq:zmq_msg_init_size[3] and linkzmq:zmq_msg_init_data[3] respectively.


Destructor
^^^^^^^^^^
[verse]
*message_t::~message_t(void)*

Calls the _zmq_msg_close()_ function, as described in linkzmq:zmq_msg_close[3].


Methods
^^^^^^^
[verse]
*void *message_t::data (void)*

Maps to the _zmq_msg_data()_ function, as described in linkzmq:zmq_msg_data[3].

[verse]
*size_t message_t::size (void)*

Maps to the _zmq_msg_size()_ function, as described in linkzmq:zmq_msg_size[3].

[verse]
*void message_t::copy (message_t '*src')*

Maps to the _zmq_msg_copy()_ function, as described in linkzmq:zmq_msg_copy[3].

[verse]
*void message_t::move (message_t '*src')*

Maps to the _zmq_msg_move()_ function, as described in linkzmq:zmq_msg_move[3].

[verse]
*message_t::rebuild(void)*
*message_t::rebuild(size_t 'size')*
*message_t::rebuild(void '*data', size_t 'size', free_fn '*ffn')*

Equivalent to calling the _zmq_msg_close()_ function followed by the
corresponding _zmq_msg_init()_ function.


Input/output multiplexing
~~~~~~~~~~~~~~~~~~~~~~~~~

[verse]
*int poll (zmq_pollitem_t *items, int nitems, long timeout = -1)*

The _poll()_ function is a namespaced equivalent of the _zmq_poll()_ function,
as described in linkzmq:zmq_poll[3].

NOTE: To obtain a 0MQ _socket_ for use in a _zmq_pollitem_t_ structure, you
should cast an instance of the _socket_t_ class to `(void *)`.


ERROR HANDLING
--------------
All errors reported by the underlying 0MQ C library functions are automatically
converted to exceptions by the C++ language binding.  The 'zmq::error_t' class
is derived from the 'std::exception' class and uses the _zmq_strerror()_
function to convert the error code to human-readable string.


EXAMPLE
-------
----
zmq::context_t ctx (1);
zmq::socket_t s (ctx, ZMQ_PUB);
s.connect ("tcp://192.168.0.115:5555");
zmq::message_t msg (100);
memset (msg.data (), 0, 100);
s.send (msg);
----


SEE ALSO
--------
linkzmq:zmq[7]


AUTHORS
-------
The 0MQ documentation was written by Martin Sustrik <sustrik@250bpm.com> and
Martin Lucina <mato@kotelna.sk>.