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.TH qlibs: socket_connect 3
.SH NAME
socket_connect \- initiate or test a socket connection to a remote IPv4/IPv6 address
.SH SYNTAX
.B #include \(dqsocket_if.h\(dq
int \fBsocket_connect4\fP(int \fIs\fR,const char \fIip\fR[4],uint16 \fIport\fR);
.br
int \fBsocket_connect6\fP(int \fIs\fR,const char \fIip\fR[16],uint16 \fIport\fR,
uint32 \fIscope_id\fR);
.br
int \fBsocket_connect\fP(int \fIs\fR,const char \fIip\fR[16],uint16 \fIport\fR,
uint32 \fIscope_id\fR);
int \fBsocket_connected\fP(int \fIs\fR);
.SH DESCRIPTION
.B socket_connect4
attempts to make a connection from TCP or UDP socket \fIs\fR to
TCP port \fIport\fR on IP address \fIip\fR.
You can call
.B socket_connect4
without calling
.BR socket_bind4 .
This has the effect as first calling
.B socket_bind4
with IP address 0.0.0.0 and port 0.
.B socket_connect6
attempts to make a connection from TCP or UDP socket \fIs\fR to
TCP port \fIport\fR on IP address \fIip\fR and \fIscope_id\fR.
The meaning of \fIscope_id\fR is dependent on the implementation and
IPv6 IP. For link-local IPv6 addresses it specifies the outgoing
interface index. From a given interface name (e.g. "eth0")
it's index can be retrieved with
.BR socket_getifidx .
\fIscope_id\fR should normally be set to 0.
You can call
.B socket_connect6
without calling
.BR socket_bind6 .
This has the effect as first calling
.B socket_bind6
with IP address :: and port 0.
.B socket_connect
attempts to make a connection from TCP socket \fIs\fR to
TCP port \fIport\fR on IP address \fIip\fR and \fIscope_id\fR
calling
.BR socket_connect6 .
If however, \fIip\fR is an IPv4 or IPv4-mapped IPv6 address
.B socket_connect4
is called instead.
Once a socket is connected, you can use the read and write
system calls to transmit data.
.B socket_connected
can be used to verify, whether a background connection failed or
succeeded, thus \fIs\fR became writable or not.
.SH EXAMPLE
#include <socket_if.h>
int \fIs\fR;
char \fIlocalip\fR[16];
char \fIremoteip\fR[16];
uint16 \fIp\fR = 0;
s = socket_tcp();
socket_bind(s,localip,p,0);
socket_connect(s,remoteip,p,0);
if (socket_connected(s) != 1)
err_tmp(""111,fatal,"unable to setup TCP connection: ");
.SH "RETURN CODES"
.BR socket_connect4 ,
.BR socket_connect6
and
.BR socket_connect
may return
.IR 0 ,
to indicate that the connection succeeded (and succeeded immediately,
if the socket is non-blocking)
.IR -1 ,
setting
.I errno
to error_inprogress or error_wouldblock, to indicate
that the socket is non-blocking
.IR -1 ,
setting
.I errno
to something else, to indicate that the connection
failed (and failed immediately, if the socket is non-blocking).
.B socket_connected
returns
.I 1
if \fIs\fR is a socket and a connection is established,
.I 0
otherwise and setting
.I errno
appropriately.
.SH "SEE ALSO"
socket_if(3),
socket_info(3),
socket_bind(3),
socket_recv(3),
socket_send(3),
socket_setup(3),
socket_tcp(3),
socket_udp(3)
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