From mboxrd@z Thu Jan 1 00:00:00 1970 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me X-Spam-Level: X-Spam-Status: No, score=-0.9 required=5.0 tests=BAYES_00,FORGED_GMAIL_RCVD, FREEMAIL_FROM autolearn=no autolearn_force=no version=3.4.4 X-Google-Thread: 103376,f3d27f1fefd7e554,start X-Google-Attributes: gid103376,public,usenet X-Google-Language: ENGLISH,ASCII-7-bit Path: g2news2.google.com!postnews.google.com!n39g2000hsh.googlegroups.com!not-for-mail From: Maciej Sobczak Newsgroups: comp.lang.ada Subject: Blocking I/O and Ravenscar Date: Fri, 21 Sep 2007 14:08:10 -0700 Organization: http://groups.google.com Message-ID: <1190408890.068176.182160@n39g2000hsh.googlegroups.com> NNTP-Posting-Host: 85.3.83.95 Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-2" X-Trace: posting.google.com 1190408890 8766 127.0.0.1 (21 Sep 2007 21:08:10 GMT) X-Complaints-To: groups-abuse@google.com NNTP-Posting-Date: Fri, 21 Sep 2007 21:08:10 +0000 (UTC) User-Agent: G2/1.0 X-HTTP-UserAgent: Mozilla/5.0 (Macintosh; U; Intel Mac OS X; en-US; rv:1.8.1.6) Gecko/20070725 Firefox/2.0.0.6,gzip(gfe),gzip(gfe) Complaints-To: groups-abuse@google.com Injection-Info: n39g2000hsh.googlegroups.com; posting-host=85.3.83.95; posting-account=ps2QrAMAAAA6_jCuRt2JEIpn5Otqf_w0 Xref: g2news2.google.com comp.lang.ada:2072 Date: 2007-09-21T14:08:10-07:00 List-Id: Basically, Ravenscar forbids any blocking operations except waiting on a protected entry or a suspension object. How can I perform a blocking I/O without breaking this restriction? Let's say I would like to read a byte from a socket. An entry with the simple barrier Is_Ready can do the job in terms of the interface, but implementation-wise it only pushes the problem away - who will set the Is_Ready flag after the byte is actually read from the blocking physical device and put in the buffer? A separate task? It would need to be non-Ravenscar - there seems to be a chicken&egg problem here. -- Maciej Sobczak http://www.msobczak.com/