Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!uunet!visix!news
From: amanda@visix.com (Amanda Walker)
Newsgroups: news.software.b
Subject: Re: C News milestone
Message-ID: <twiw2ymjwa@visix.com>
Date: 11 Dec 90 04:07:50 GMT
References: <4_377B@xds13.ferranti.com> <1990Nov27.230750.3478@looking.on.ca> <KHW7.C@xds13.ferranti.com> <1990Dec7.114243.12454@warwick.ac.uk>
Sender: news@visix.com
Reply-To: amanda@visix.com (Amanda Walker)
Organization: Visix Software Inc., Reston, VA
Lines: 44

Here's what I use to generate C News message IDs:

--------

#include <stdio.h>
#include <time.h>

char charset[] = "abcdefghijklmnopqrstuvwxyz012345";    /* 32 "digits" */

main()
{
        unsigned long t;
        unsigned short p;

        time(&t);
        p = getpid();

        printf("%c%c%c%c%c%c%c%c%c%c",
                charset[(t >> 25) & 31],
                charset[(t >> 20) & 31],
                charset[(t >> 15) & 31],
                charset[(t >> 10) & 31],
                charset[(t >>  5) & 31],
                charset[t & 31],
                charset[(p >> 10) & 31],
                charset[(p >> 5) & 31],
                charset[p & 31],
                charset[((t >> 30) & 3) + ((p >> 13) & 4)]); /* extra bits */
}

--------

It assumes that the time is 32 bits, and that the PID is 16, but
changing it to cope with other sizes is trivial.

It's not quite a minimum number of characters, but 10 characters seems close
enough for Usenet, and they're nice well-behaved alphanumeric strings.


Amanda Walker
Visix Software Inc.
-- 
"I have never seen anything fill up a vacuum so fast and still suck."
		--Rob Pike commenting on the X Window System