Custom Query (1030 matches)

Read-char-no-hang is supposed to return NIL if there is no more input available from the stream. But it hangs in the following particular example, when it's trying to read from the output stream of an external program, and that stream is still open but there's nothing on it:

? (defparameter *cat-process*
    (run-program "cat" nil
               :input :stream
               :output :stream
               :wait nil))
*CAT-PROCESS*
? (write-line "hi" (external-process-input-stream *cat-process*))
"hi"
? (finish-output (external-process-input-stream *cat-process*))
NIL
? (read-char-no-hang (external-process-output-stream *cat-process*))
#\h
? (read-char-no-hang (external-process-output-stream *cat-process*))
#\i
? (read-char-no-hang (external-process-output-stream *cat-process*))
#\Newline
? (read-char-no-hang (external-process-output-stream *cat-process*))
;; (hangs)

Another strange thing about the same situation is that LISTEN on that stream returns T even when there's no more to be read.

To reproduce:

• open clozure cl
• in the listener type (ccl::choose-file-dialog
• drag any file in the dialogs main view
• notice that the application crashes and the following error is reported in the console:

  > Error: FLOATING-POINT-INVALID-OPERATION detected
  > While executing: (:INTERNAL GUI::|-[LispApplication sendEvent:]|), in process Initial(0).
  

Although it's implementation dependent what initial value *print-pprint-dispatch* is, NIL is rather inconvenient, since it causes set-pprint-dispatch without explicit table to error.