From: Tom Lane <tgl@sss.pgh.pa.us>
To: Thomas Munro <thomas.munro@gmail.com>
cc: Heikki Linnakangas <hlinnaka@iki.fi>,
        =?UTF-8?Q?Bastien_Roucari=C3=A8s?= <rouca@debian.org>,
        pgsql-bugs@lists.postgresql.org
Subject: Re: Detection of hadware feature => please do not use signal
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Comments: In-reply-to Thomas Munro <thomas.munro@gmail.com>
	message dated "Fri, 01 Nov 2024 17:28:53 +1300"
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Date: Fri, 01 Nov 2024 00:44:35 -0400
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Thomas Munro <thomas.munro@gmail.com> writes:
> On Fri, Nov 1, 2024 at 7:25 AM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> It occurs to me to wonder whether the existing code works on Windows.
>> Windows-on-ARM wasn't a thing we thought about in 2018, but it's
>> a reasonable target now.

> I looked into that[1] and decided that I was going to ignore it
> completely, because:
> [ oodles o' details ]

Hmm.  So it seems like we could do this:

* Linux, FreeBSD, OpenBSD: do run-time test as recommended
* Windows, macOS: assume that supported ARM hardware can do this
* anything else: assume no hardware CRC

The only thing I'd be even a bit sad about there is not having
NetBSD support.  Maybe we just need to research that a bit more,
or maybe we have to wait for/lobby for them to do what the other
BSDen have done.  But in any case I'm not seeing NetBSD-on-ARM
as a platform that's important enough to block movement on this,
let alone anything else in the "anything else" category.

An alternative to "assume no hardware CRC" could be

* anything else: use the existing SIGILL test

But I do sympathize with Bastien's concerns about that.

			regards, tom lane