From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brantley Coile Content-type: multipart/alternative; boundary="Apple-Mail=_DFCA6170-D4C4-4279-99A7-E9C324926BEB" Message-id: MIME-version: 1.0 (Mac OS X Mail 9.0 \(3094\)) Date: Thu, 26 Nov 2015 18:55:10 -0500 References:

<20151125160347.GN20646@sigint.cs.purdue.edu>

<79F2255E-5E76-43E8-83B3-0DFB2CD34AC7@bitblocks.com> <3175949A-26D0-4C4A-BB7D-4E5A3EA7F8B7@me.com>

To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> In-reply-to: Subject: Re: [9fans] Undefined Behaviour in C Topicbox-Message-UUID: 78bd088a-ead9-11e9-9d60-3106f5b1d025 --Apple-Mail=_DFCA6170-D4C4-4279-99A7-E9C324926BEB Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 I did a port just like that (DTS Generic Unix) just to see what it would = be like. It was awful. I=E2=80=99ll never do that again. > On Nov 26, 2015, at 6:14 PM, Steve Simon wrote: >=20 >=20 > I don't know about the PDP but the VAX allowed access to address zero. >=20 > Even more insidious, it allowed you to dereference a null pointer and = guaranteed it would contain a zero, which resulted in many tiresome = portability issues - I used Interdatas at the time, which faulted on a = read at address zero. >=20 > -Steve >=20 >=20 > On 26 Nov 2015, at 17:48, Bakul Shah > wrote: >=20 >> Good points! Though 0 was a valid address on pdp11, right?=20 >>>>>> =20 --Apple-Mail=_DFCA6170-D4C4-4279-99A7-E9C324926BEB Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8 I did a port just like that (DTS Generic Unix) just to see = what it would be like. It was awful. I=E2=80=99ll never do that = again.

On Nov 26, 2015, at 6:14 PM, Steve Simon = <steve@quintile.net> wrote:

I don't know about the = PDP but the VAX allowed access to address zero.

Even more insidious, it allowed you to = dereference a null pointer and guaranteed it would contain a zero, which = resulted in many tiresome portability issues - I used Interdatas at the = time, which faulted on a read at address zero.

-Steve

On = 26 Nov 2015, at 17:48, Bakul Shah <bakul@bitblocks.com>= wrote:

Good points! Though 0 = was a valid address on pdp11, right?

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