GNU bug report logs - #30066
'get-bytevector-some' returns only 1 byte from unbuffered ports

Previous Next

Full log

View this message in rfc822 format

From: ludo <at> gnu.org (Ludovic Courtès)
To: 30066 <at> debbugs.gnu.org
Cc: Andy Wingo <wingo <at> igalia.com>
Subject: bug#30066: 'get-bytevector-some' returns only 1 byte from unbuffered ports
Date: Wed, 10 Jan 2018 16:02:10 +0100

As discussed on IRC, ‘get-bytevector-some’ returns only 1 byte from
unbuffered ports:

--8<---------------cut here---------------start------------->8---
scheme@(guile-user)> (call-with-input-string "foo"
		       (lambda (port)
			 (setvbuf port _IONBF)
			 (get-bytevector-some port)))
$11 = #vu8(102)
scheme@(guile-user)> (version)
$12 = "2.2.3"
--8<---------------cut here---------------end--------------->8---

Strictly speaking it’s valid, but in practice it’s not very useful.

AFAICS, we lack a way to do the equivalent of:

  read (fd, buf, sizeof buf);

‘get-bytevector-n!’ is different because it blocks until it has read
COUNT bytes or EOF is reached.  So ‘get-bytevector-some’ could play this
role, but it doesn’t.

Thoughts?

Ludo’.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.