make.socket {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)
print.socket(socket)

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)
}
daytime()  ## only works if your computer runs this service
daytime("ntp.demon.co.uk")

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