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;; Call with standard output
(print-int (current-output-port) 314159)
;; Redirection to a file. Note that the port is automatically flushed
;; (via force-output) before calling the C function, and that the C
;; function gets a temporary "FILE" stream, which is closed after the
;; call. So you can simply mix Scheme and C output.
(with-output-to-file "test.out"
(lambda ()
(display 4711)
(newline)
(print-int (current-output-port) 314159)
(display 815)
(newline)))
;; Redirection to a string or soft port won't work --
;; we can only handle file ports.
(catch #t
(lambda ()
(with-output-to-string
(lambda ()
(print-int (current-output-port) 314159))))
(lambda args
(display "Below shows that attempting to write to a string or soft port will result in a wrong-type-error...")
(newline)
(write args) (newline)))
;; Read from a file port. Note that it is a bad idea to mix Scheme and
;; C input because of buffering, hence the call to seek to rewind the file.
(with-input-from-file "test.out"
(lambda ()
(seek (current-input-port) 0 SEEK_SET)
(display (read-int (current-input-port)))
(newline)))
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