(import (chicken foreign))

(define (get-c-file port)
  (define extract-c-file
    (foreign-lambda* c-pointer ((scheme-object port))
                     "C_return(C_block_item(port, 0));"))
  (assert (port? port))
  (assert (eq? 'stream (##sys#slot port 7)))
  (extract-c-file port))