mirror of
https://github.com/zeromq/libzmq.git
synced 2024-12-25 22:30:51 +08:00
101 lines
3.8 KiB
Plaintext
101 lines
3.8 KiB
Plaintext
= zmq_connect(3)
|
|
|
|
|
|
== NAME
|
|
zmq_connect - create outgoing connection from socket
|
|
|
|
|
|
== SYNOPSIS
|
|
*int zmq_connect (void '*socket', const char '*endpoint');*
|
|
|
|
|
|
== DESCRIPTION
|
|
The _zmq_connect()_ function connects the 'socket' to an 'endpoint' and then
|
|
accepts incoming connections on that endpoint.
|
|
|
|
The 'endpoint' is a string consisting of a 'transport'`://` followed by an
|
|
'address'. The 'transport' specifies the underlying protocol to use. The
|
|
'address' specifies the transport-specific address to connect to.
|
|
|
|
0MQ provides the the following transports:
|
|
|
|
'tcp':: unicast transport using TCP, see xref:zmq_tcp.adoc[zmq_tcp]
|
|
'ipc':: local inter-process communication transport, see xref:zmq_ipc.adoc[zmq_ipc]
|
|
'inproc':: local in-process (inter-thread) communication transport, see xref:zmq_inproc.adoc[zmq_inproc]
|
|
'pgm', 'epgm':: reliable multicast transport using PGM, see xref:zmq_pgm.adoc[zmq_pgm]
|
|
'vmci':: virtual machine communications interface (VMCI), see xref:zmq_vmci.adoc[zmq_vmci]
|
|
'udp':: unreliable unicast and multicast using UDP, see xref:zmq_udp.adoc[zmq_udp]
|
|
|
|
Every 0MQ socket type except 'ZMQ_PAIR' and 'ZMQ_CHANNEL' supports one-to-many and many-to-one
|
|
semantics. The precise semantics depend on the socket type and are defined in
|
|
xref:zmq_socket.adoc[zmq_socket]
|
|
|
|
NOTE: for most transports and socket types the connection is not performed
|
|
immediately but as needed by 0MQ. Thus a successful call to _zmq_connect()_
|
|
does not mean that the connection was or could actually be established.
|
|
Because of this, for most transports and socket types the order in which
|
|
a 'server' socket is bound and a 'client' socket is connected to it does not
|
|
matter. The _ZMQ_PAIR_ and _ZMQ_CHANNEL_ sockets are an exception, as they do not automatically
|
|
reconnect to endpoints.
|
|
|
|
NOTE: following a _zmq_connect()_, for socket types except for ZMQ_ROUTER,
|
|
the socket enters its normal 'ready' state. By contrast, following a
|
|
_zmq_bind()_ alone, the socket enters a 'mute' state in which the socket
|
|
blocks or drops messages according to the socket type, as defined in
|
|
xref:zmq_socket.adoc[zmq_socket] A ZMQ_ROUTER socket enters its normal 'ready' state
|
|
for a specific peer only when handshaking is complete for that peer, which
|
|
may take an arbitrary time.
|
|
|
|
NOTE: for some socket types, multiple connections to the same endpoint
|
|
don't really make sense
|
|
(see https://github.com/zeromq/libzmq/issues/788).
|
|
For those socket types, any attempt to connect to an already connected endpoint
|
|
is silently ignored (i.e., returns zero). This behavior applies to ZMQ_DEALER,
|
|
ZMQ_SUB, ZMQ_PUB, and ZMQ_REQ socket types.
|
|
|
|
|
|
== RETURN VALUE
|
|
The _zmq_connect()_ function returns zero if successful. Otherwise it returns
|
|
`-1` and sets 'errno' to one of the values defined below.
|
|
|
|
|
|
== ERRORS
|
|
*EINVAL*::
|
|
The endpoint supplied is invalid.
|
|
*EPROTONOSUPPORT*::
|
|
The requested 'transport' protocol is not supported.
|
|
*ENOCOMPATPROTO*::
|
|
The requested 'transport' protocol is not compatible with the socket type.
|
|
*ETERM*::
|
|
The 0MQ 'context' associated with the specified 'socket' was terminated.
|
|
*ENOTSOCK*::
|
|
The provided 'socket' was invalid.
|
|
*EMTHREAD*::
|
|
No I/O thread is available to accomplish the task.
|
|
|
|
|
|
== EXAMPLE
|
|
.Connecting a subscriber socket to an in-process and a TCP transport
|
|
----
|
|
/* Create a ZMQ_SUB socket */
|
|
void *socket = zmq_socket (context, ZMQ_SUB);
|
|
assert (socket);
|
|
/* Connect it to an in-process transport with the address 'my_publisher' */
|
|
int rc = zmq_connect (socket, "inproc://my_publisher");
|
|
assert (rc == 0);
|
|
/* Connect it to the host server001, port 5555 using a TCP transport */
|
|
rc = zmq_connect (socket, "tcp://server001:5555");
|
|
assert (rc == 0);
|
|
----
|
|
|
|
|
|
== SEE ALSO
|
|
* xref:zmq_bind.adoc[zmq_bind]
|
|
* xref:zmq_socket.adoc[zmq_socket]
|
|
* xref:zmq.adoc[zmq]
|
|
|
|
|
|
== AUTHORS
|
|
This page was written by the 0MQ community. To make a change please
|
|
read the 0MQ Contribution Policy at <https://zeromq.org/how-to-contribute/>.
|