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From: Paul Jackson <pj@sgi.com>
To: "Paul Rolland" <rol@witbe.net>
Cc: hancockr@shaw.ca, kernel@wildsau.enemy.org, linux-kernel@vger.kernel.org
Subject: Re: procfs uglyness caused by "cat"
Date: Tue, 14 Mar 2006 09:59:40 -0800	[thread overview]
Message-ID: <20060314095940.7be639e7.pj@sgi.com> (raw)
In-Reply-To: <001901c6477c$a46b4c90$b600a8c0@cortex>

Paul Rolland wrote:
> is funny enough...

You used the stdio routine fread - which buffers in user space.  It
does a single read, and then feeds you the characters as you ask for
them, out of its stdio buffer.

Try the following program, which doesn't buffer:

main()
{
    char c;
    int fd = open("/proc/uptime", 0);
    while (read(fd, &c, 1) == 1) {
        write(1, &c, 1);
        sleep(1);
    }
}

-- 
                  I won't rest till it's the best ...
                  Programmer, Linux Scalability
                  Paul Jackson <pj@sgi.com> 1.925.600.0401

  reply	other threads:[~2006-03-14 17:59 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <5Qfgo-3At-15@gated-at.bofh.it>
2006-03-14 14:35 ` procfs uglyness caused by "cat" Robert Hancock
2006-03-14 15:33   ` Paul Rolland
2006-03-14 17:59     ` Paul Jackson [this message]
2006-03-14 18:45       ` Paul Rolland
2006-03-15  8:06   ` Herbert Rosmanith
2006-03-15  8:23   ` Herbert Rosmanith
2006-03-14 10:43 Herbert Rosmanith
2006-03-14 15:57 ` Paul Jackson

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