---
name: "socket_connect4"
section: "3"
platform: "linux"
package: "libowfat-dev"
version: "0.32-5"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/socket_connect4"
---

# socket\_connect4(3)

attempt to make a TCP connection

## NAME

socket\_connect4 - attempt to make a TCP connection

## SYNTAX

**#include \<libowfat/socket.h\>**

int **socket\_connect4**(int *s*,const char *ip*\[4\],uint16 *port*);

## DESCRIPTION

socket\_connect4 attempts to make a connection from TCP socket *s* to TCP port *port* on IP address *ip*.

socket\_connect4 may return

- •

  0, to indicate that the connection succeeded (and succeeded immediately, if the socket is non-blocking)

- •

  \-1, setting errno to error\_inprogress or error\_wouldblock, to indicate that the socket is non-blocking

- •

  \-1, setting errno to something else, to indicate that the connection failed (and failed immediately, if the socket is non-blocking).

When a background connection succeeds or fails, *s* becomes writable; you can use socket\_connected to see whether the connection succeeded.  If the connection failed, socket\_connected returns 0, setting errno appropriately.

Once a TCP socket is connected, you can use the read and write system calls to transmit data.

You can call socket\_connect4 without calling socket\_bind4.  This has the effect as first calling socket\_bind4 with IP address 0.0.0.0 and port 0.

## EXAMPLE

  \#include \<libowfat/socket.h\>

  int *s*;\
   char *ip*\[4\];\
   uint16 *p*;

  *s* = socket\_tcp4();\
   socket\_bind4(s,ip,p);\
   socket\_connect4(s,ip,p);

## SEE ALSO

[socket\_connect6(3)](/socket_connect6/3.md), [socket\_fastopen\_connect4(3)](/socket_fastopen_connect4/3.md)