showConnections {base}R Documentation

Display Connections

Description

Display aspects of connections.

Usage

showConnections(all = FALSE)
getConnection(what)
closeAllConnections()

stdin()
stdout()
stderr()

Arguments

all logical: if true all connections, including closed ones and the standard ones are displayed. If false only open user-created connections are included.
what integer: a row number of the table given by showConnections.

Details

stdin(), stdout() and stderr() are standard connections corresponding to input, output and error on the console respectively (and not necessarily to file streams). They are text-mode connections of class "terminal" which cannot be opened or closed, and are read-only, write-only and write-only respectively. The stdout() and stderr() connections can be re-directed by sink.

showConnections returns a matrix of information. If a connection object has been lost or forgotten, getConnection will take a row number from the table and return a connection object for that connection, which can be used to close the connection, for example.

closeAllConnections closes (and destroys) all open user connections, restoring all sink diversions as it does so.

Value

stdin(), stdout() and stderr() return connection objects.
showConnections returns a character matrix of information with a row for each connection, by default only for open non-standard connections.
getConnection returns a connection object, or NULL.

See Also

connections

Examples

showConnections(all = TRUE)

textConnection(letters)
# oops, I forgot to record that one
showConnections()
#  class     description      mode text   isopen   can read can write
#3 "letters" "textConnection" "r"  "text" "opened" "yes"    "no"     
## Not run: close(getConnection(3))

showConnections()

[Package base version 2.1.0 Index]