S9 LIB  (standard-error-port)                ==>  #<output-port>
        (call-with-stderr procedure^1)       ==>  object
        (with-output-to-stderr procedure^0)  ==>  unspecific

        (load-from-library "standard-error.scm")

STANDARD-ERROR-PORT returns an output-file for accessing the Unix
standard error file descriptor (stderr). CALL-WITH-STDERR passes
that output-file to a unary procedure, which may use it for writing
data to stderr. WITH-OUTPUT-TO-STDERR temporarily sets the current
output port) to the stderr descriptor while running the given nullary
procedure. CALL-WITH-STDERR returns the value returned by PROCEDURE^1.

Instead of STANDARD-ERROR-PORT you may want to use the built-in
CURRENT-ERROR-PORT procedure in S9fES Reimagined.

(call-with-stderr
  (lambda (stderr)
    (display "Something went wrong!" stderr)
    (newline stderr)))                       ==> unspecific
