close-port - close a port

(import (rnrs))                     ;R6RS
(import (rnrs io ports))            ;R6RS
(import (scheme base))              ;R7RS

(close-port port)

Closes the port, rendering the port incapable of delivering or accepting data. If port is an output port, it is flushed before being closed. This has no effect if the port has already been closed. A closed port is still a port.

R6RS

If port is a custom port then the closer procedure is called before the port is really closed.

Returns unspecified values.

(define p (open-output-file "hello.txt"))
(display "Hello, world\n" p)
(close-port p)

Ports are often connected to some limited resource, such as a file descriptor. Closing ports is important to avoid resource leaks. Some implementations will garbage collect ports, but this is not required.

This procedure is new in R6RS and R7RS.

This procedure can raise exceptions with the following condition types:

&assertion (R6RS)

The wrong number of arguments was passed or an argument was outside its domain.

&i/o-write (R6RS)

There was buffered data in the port and a write error while the port was being flushed.

&i/o-port (R6RS)

This condition specifies the port object related to the &i/o-write condition.

R7RS

The assertions described above are errors. Implementations may signal an error, extend the procedure's domain of definition to include such arguments, or fail catastrophically.

close-input-port(3scm), call-with-port(3scm)

R6RS, R7RS

This page is part of the scheme-manpages project. It includes materials from the RnRS documents. More information can be found at https://weinholt.se/scheme/manpages/.

It is often better to use call-with-port(3scm) or one of the related procedures. They make it easier to ensure that a port is closed when an exception is raised.