On Thu, Dec 18, 2025 at 10:18 AM Vibhu Mohindra <vibhu.mohindra@gmail.com> wrote:

-------- Forwarded Message --------
Subject: Re: READ-SEQUENCE and USOCKET
Date: Thu, 18 Dec 2025 10:14:57 +0100
From: Vibhu Mohindra <vibhu.mohindra@gmail.com>
To: pro@common-lisp.net

How are you doing Marco?

I'm looking at usocket-0.8.4. It may be worth exploring some of these
aspects I see in its code:
1. option.lisp allows: (setf (socket-option mysocket :receive-timeout) ...)
2. usocket.lisp defines a generic socket-receive. It's only implemented for
UDP sockets but I don't see why it shouldn't be implementable for
stream-sockets too.

Otherwise I don't see a better solution in usocket than inefficiently
checking for and reading a byte at a time, like this.

(defun read-available-vector (vector socket &key (start 0) (end nil))
"Reads whatever is presently available in SOCKET without hanging.
SOCKET and VECTOR are assumed to have elts of type (unsigned-byte 8).
Returns first unwritten position in VECTOR and whether at end-of-file."
(when (null end) (setq end (length vector)))
(assert (<= 0 start end (length vector)))
(flet ((socket-readyp ()
(wait-for-input socket :timeout 0 :ready-only t)))
(do ((i start (1+ i)))
((or (>= i end) (not (socket-readyp)))
(values i nil))
(let ((b (read-byte (socket-stream stream) nil nil)))
(unless b (return (values i t)))
(setf (aref vector i) b)))))

--
Vibhu