21.2.33 with-open-stream [Macro]

with-open-stream (var stream) {declaration}* {form}*
⇒ {result}*

Arguments and Values::

var—a variable name.

stream—a form; evaluated to produce a stream.

declaration—a declare expression; not evaluated.

forms—an implicit progn.

results—the values returned by the forms.

Description::

with-open-stream performs a series of operations on stream, returns a value, and then closes the stream.

Var is bound to the value of stream, and then forms are executed as an implicit progn. stream is automatically closed on exit from with-open-stream, no matter whether the exit is normal or abnormal.

The stream has dynamic extent; its extent ends when the form is exited.

The consequences are undefined if an attempt is made to assign the the variable var with the forms.

Examples::

 (with-open-stream (s (make-string-input-stream "1 2 3 4"))
    (+ (read s) (read s) (read s))) ⇒  6

Side Effects::

The stream is closed (upon exit).

See Also::

close