Nonblocking get-bytevector-n bug?

[Marko Rauhamaa]

Guile 2.0.11 provides:

   get-bytevector-n
   get-bytevector-n!
   get-bytevector-some

Of these, only get-bytevector-some seems to behave as expected when the
port is nonblocking:

========================================================================
(use-modules (rnrs io ports)
             (rnrs bytevectors))

(let ((port (fdes->inport 0)))
  (fcntl port F_SETFL (logior O_NONBLOCK (fcntl port F_GETFL)))
  (let loop ()
    (catch 'system-error
      (lambda ()
        (format #t "~s\n" (get-bytevector-some port)))
      (lambda syserr
        (format #t "err ~s\n" (system-error-errno syserr))))
    (sleep 1)
    (loop)))
========================================================================

If you replace (get-bytevector-some port) with
(get-bytevector-n port 8192) or (get-bytevector-n! port bv 0 8192),
no partial data is returned.

The problem with get-bytevector-some is that there is no limit to how
many bytes might be returned. In practice, I see that the amount is
capped at 4096 bytes, but the documentation does not guarantee any
limit.


Marko