make.socket               package:base               R Documentation

Create a Socket Connection

Description:

     With `server = FALSE' attempts to open a client socket to the
     specified port and host. With `server = TRUE' listens on the
     specified port for a connection and then returns a server socket.
     It is a good idea to use `on.exit' to ensure that a socket is
     closed, as you only get 64 of them.

Usage:

     make.socket(host = "localhost", port, fail = TRUE, server = FALSE)

Arguments:

    host: name of remote host

    port: port to connect to/listen on

    fail: failure to connect is an error?

  server: a server socket?

Value:

     An object of class `"socket"'. 

  socket: socket number. This is for internal use

    port: port number of the connection

    host: name of remote computer

Warning:

     I don't know if the connecting host name returned when `server =
     TRUE' can be trusted. I suspect not.

Author(s):

     Thomas Lumley

References:

     Adapted from Luke Tierney's code for `XLISP-Stat', in turn based
     on code from Robbins and Robbins "Practical UNIX Programming"

See Also:

     `close.socket', `read.socket'

Examples:

     daytime <- function(host = "localhost"){
         a <- make.socket(host, 13)
         on.exit(close.socket(a))
         read.socket(a)
     }
     ## Offical time (UTC) from US Naval Observatory
     daytime("tick.usno.navy.mil")

