[Top][All Lists]

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

a little puzzle

From: Andy Wingo
Subject: a little puzzle
Date: Fri, 08 Oct 2010 19:14:34 +0200
User-agent: Gnus/5.13 (Gnus v5.13) Emacs/23.2 (gnu/linux)

Put this in your REPL and smoke it:

    (define* (make-me-a-socket #:key
                               (host #f)
                               (addr (if host (inet-aton host) INADDR_LOOPBACK))
                               (port 37146))
      (let ((server (socket PF_INET SOCK_STREAM 0)))
        (setsockopt server SOL_SOCKET SO_REUSEADDR 1)
        (bind server AF_INET addr port)
        (listen server 5)

    (sigaction SIGINT (lambda (sig) (throw 'foo)))

    (define s (make-me-a-socket))
    (accept s) ; Now Ctrl-C

What do you expect to happen here?

Probably not this:

    ERROR: In procedure accept:
    ERROR: Interrupted system call
    Entering a new prompt.  Type `,bt' for a backtrace or `,q' to continue.
    scheme@(guile-user) [1]> 
    Throw to key `foo' with args `()' while reading expression.
    scheme@(guile-user) [1]> 

That's right: two throws for the price of one! The interrupted syscall,
and then the asynchronous signal. Fun...


reply via email to

[Prev in Thread] Current Thread [Next in Thread]