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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Thomas Munro <thomas.munro@gmail.com>
Cc: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Cc: Justin Pryzby <pryzby@telsasoft.com>
Cc: PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Subject: Re: pg15b1: FailedAssertion("val > base", File: "...src/include/utils/relptr.h", Line: 67, PID: 30485)
Date: Tue, 31 May 2022 18:39:23 -0400
Message-ID: <355850.1654036763@sss.pgh.pa.us> (raw)
In-Reply-To: <CA+TgmoaWBD32wMe7DvgUqQYUCT0+oOQW8Yh8atKX+1jtZHFs7Q@mail.gmail.com>
References: <20220519193839.GT19626@telsasoft.com>
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Robert Haas <robertmhaas@gmail.com> writes:
> On Tue, May 31, 2022 at 6:14 PM Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> However, now that I've corrected that mistaken image ... I wonder if
>> it could make sense to redefine relptr as self-relative?  That ought
>> to provide some notational savings since you'd only need to carry
>> around the relptr's own address not that plus a base address.
>> Probably not something to consider for v15 though.

> I think that would be pretty hard to make work, since copying around a
> relative pointer would change its meaning. Code like "relptr_foo x =
> *y" would be broken, for example, but the compiler would not complain.

Sure, but the current definition is far from error-proof as well:
nothing stops you from using the wrong base address with a relptr's
value.  Anyway, it's just idle speculation at this point.

			regards, tom lane





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  Subject: Re: pg15b1: FailedAssertion("val > base", File: "...src/include/utils/relptr.h", Line: 67, PID: 30485)
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