'\" t
.\"     Title: zmq_connect_peer
.\"    Author: [see the "AUTHORS" section]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 10/23/2023
.\"    Manual: 0MQ Manual
.\"    Source: 0MQ 4.3.5
.\"  Language: English
.\"
.TH "ZMQ_CONNECT_PEER" "3" "10/23/2023" "0MQ 4\&.3\&.5" "0MQ Manual"
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.SH "NAME"
zmq_connect_peer \- create outgoing connection from socket and return the connection routing id in thread\-safe and atomic way\&.
.SH "SYNOPSIS"
.sp
\fBuint32_t zmq_connect_peer (void \fR\fB\fI*socket\fR\fR\fB, const char \fR\fB\fI*endpoint\fR\fR\fB);\fR
.SH "DESCRIPTION"
.sp
The \fIzmq_connect_peer()\fR function connects a \fIZMQ_PEER\fR socket to an \fIendpoint\fR and then returns the endpoint \fIrouting_id\fR\&.
.sp
The \fIendpoint\fR is a string consisting of a \fItransport\fR:// followed by an \fIaddress\fR\&. The \fItransport\fR specifies the underlying protocol to use\&. The \fIaddress\fR specifies the transport\-specific address to connect to\&.
.sp
The function is supported only on the \fIZMQ_PEER\fR socket type and would return 0 with \fIerrno\fR set to \fIENOTSUP\fR otherwise\&.
.sp
The \fIzmq_connect_peer()\fR support the following transports:
.PP
\fItcp\fR
.RS 4
unicast transport using TCP, see
\fBzmq_tcp\fR(7)
.RE
.PP
\fIipc\fR
.RS 4
local inter\-process communication transport, see
\fBzmq_ipc\fR(7)
.RE
.PP
\fIinproc\fR
.RS 4
local in\-process (inter\-thread) communication transport, see
\fBzmq_inproc\fR(7)
.RE
.PP
\fIws\fR
.RS 4
unicast transport using WebSockets, see
\fBzmq_ws\fR(7)
.RE
.PP
\fIwss\fR
.RS 4
unicast transport using WebSockets over TLS, see
\fBzmq_wss\fR(7)
.RE
.SH "RETURN VALUE"
.sp
The \fIzmq_connect_peer()\fR function returns the peer \fIrouting_id\fR if successful\&. Otherwise it returns 0 and sets \fIerrno\fR to one of the values defined below\&.
.SH "ERRORS"
.PP
\fBEINVAL\fR
.RS 4
The endpoint supplied is invalid\&.
.RE
.PP
\fBEPROTONOSUPPORT\fR
.RS 4
The requested
\fItransport\fR
protocol is not supported with
\fIZMQ_PEER\fR\&.
.RE
.PP
\fBENOCOMPATPROTO\fR
.RS 4
The requested
\fItransport\fR
protocol is not compatible with the socket type\&.
.RE
.PP
\fBETERM\fR
.RS 4
The 0MQ
\fIcontext\fR
associated with the specified
\fIsocket\fR
was terminated\&.
.RE
.PP
\fBENOTSOCK\fR
.RS 4
The provided
\fIsocket\fR
was invalid\&.
.RE
.PP
\fBEMTHREAD\fR
.RS 4
No I/O thread is available to accomplish the task\&.
.RE
.PP
\fBENOTSUP\fR
.RS 4
The socket is not of type
\fIZMQ_PEER\fR\&.
.RE
.PP
\fBEFAULT\fR
.RS 4
The
\fIZMQ_IMMEDIATE\fR
option is set on the socket\&.
.RE
.SH "EXAMPLE"
.PP
\fBConnecting a peer socket to a TCP transport and sending a message\fR. 
.sp
.if n \{\
.RS 4
.\}
.nf
/* Create a ZMQ_SUB socket */
void *socket = zmq_socket (context, ZMQ_PEER);
assert (socket);
/* Connect it to the host server001, port 5555 using a TCP transport */
uint32_t routing_id = zmq_connect (socket, "tcp://server001:5555");
assert (routing_id == 0);
/* Sending a message to the peer  */
zmq_msg_t msg;
int rc = zmq_msg_init_data (&msg, "HELLO", 5, NULL, NULL);
assert (rc == 0);
rc = zmq_msg_set_routing_id (&msg, routing_id);
assert (rc == 0);
rc = zmq_msg_send (&msg, socket, 0);
assert (rc == 5);
rc = zmq_msg_close (&msg);
assert (rc == 0);
.fi
.if n \{\
.RE
.\}
.sp
.SH "SEE ALSO"
.sp
\fBzmq_connect\fR(3) \fBzmq_bind\fR(3) \fBzmq_socket\fR(3) \fBzmq\fR(7)
.SH "AUTHORS"
.sp
This page was written by the 0MQ community\&. To make a change please read the 0MQ Contribution Policy at \m[blue]\fBhttp://www\&.zeromq\&.org/docs:contributing\fR\m[]\&.