Cind language documentation

Socket linked library

The socket library provides functions for IPv4 and IPv6 TCP/IP connection protocol,
which may be called from Cind programs.

To connect socket library use syntax of getting linked libraries, with "socket" word as the second argument:

var lsocket = @("lib","socket");

For more about connecting libraries see Using linked libraries.


List of functions available from the socket library:

function args type of arguments type of result description
connect 2 (string name,int port) int creates the socket and connects to given server on given port number, returns the socket as number.
send 4 (int socket,sheet data,int off,int count) int sends a data on a socket, returns number of bytes sent.
recv 3 (int socket,sheet data,int count) int receives a data from a socket, returns number of bytes received.
shutdown 2 (int socket,int how) - shut down part of the connection. 'how' parameter values: 1 - close receiving, 2 - close sending, 3 - close both.
close 1 (int socket) - closes a socket.
bind 1 (int port) int creates the socket and bind to given port number, returns the socket as number.
listen 2 (int socket,int qsize) - listen for connection on a given socket, setting also the length of waiters queue.
accept 1 (int socket) int accepts another incomming connection, returns the socket of the new connection.
getPeerHost 3 (int socket,int ipv,sheet name) int gets the IP number of the connection, the 'ipv' parameter should be 4 or 6, saying, that resuling string must be in IPv4 or IPv6 format, returns number of written bytes.
getPeerPort 3 (int socket) int returns the port number of the connection of given socket.


  • Those functions allows to implement client and server TCP/IP applications.
  • The server may accpet both IPv4 and IPv6 connections.
  • The IP number of the calling peer may be readed in visual form in both IPv4 and IPv6 formats.
  • The data parameter of send and recv functions is a part of memory, in which data will be written or readed from (see Sheet object).

Example of usage

// get socket library var libsocket = @("lib","socket"); // connect to some point in the internet int socket = libsocket.connect("",80); // send data { sheet data = (sheet)"GET / HTTP/1.0\r\n\r\n"; int datalen = data.size(); int was = libsocket.send(socket,data,0,datalen); // assuming here that all data has been sent (if not, send them in some loop) } // receive data { sheet recBuffer = ((sheet)"").setSize(512); int was; while((was = libsocket.recv(socket,recBuffer,512)) > 0) { sheet receivedPart = recBuffer.subSheet(0,was); host.print(receivedPart); } } // close socket libsocket.close(socket);

Cind programming language 1.0.4