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From: Junio C Hamano <gitster@pobox.com>
To: Jeff King <peff@peff.net>
Cc: git@vger.kernel.org
Subject: Re: [PATCH] builtin/mv.c: use correct type to compute size of an array element
Date: Thu, 07 Jul 2022 13:25:33 -0700	[thread overview]
Message-ID: <xmqqfsjczn42.fsf@gitster.g> (raw)
In-Reply-To: <YscpDTgwxUko/aZM@coredump.intra.peff.net> (Jeff King's message of "Thu, 7 Jul 2022 14:42:21 -0400")

Jeff King <peff@peff.net> writes:

> On Wed, Jul 06, 2022 at 07:02:18PM -0700, Junio C Hamano wrote:
>
>>    * Should we in general use sizeof(TYPE) in these cases, instead
>>      of the size of the zeroth element, e.g.
>> 
>>  		memmove(source + i, source + i + 1,
>> 			n * sizeof(source[i]));
>>     
>>      It would have been caught by the above Coccinelle rule (we are
>>      taking the size of *dst).
>
> I'm not sure I understand this. As you noted in a later email, using
> sizeof(TYPE) is less maintainable if the type of "source" changes.

Sorry for a typo or thinko, whichever one you like ;-)

> But
> later you mention using "*source" instead of "source[i]". I don't think
> there is a particular reason to prefer one over the other from the
> compiler perspective. I find "*source" more idiomatic (but better still
> of course is MOVE_ARRAY, which removes the choice entirely).

Yes, I wrote source[i] there only because I found it somewhat
awkward to write source[0] or *source there, when the moved
(sub)array is from the index 'i' to the end.  *(source + i) would
have matched the intention better but it still is awkward.

      reply	other threads:[~2022-07-07 20:25 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-07-07  2:02 [PATCH] builtin/mv.c: use correct type to compute size of an array element Junio C Hamano
2022-07-07  5:52 ` [PATCH v2] builtin/mv.c: use the MOVE_ARRAY() macro instead of memmove() Junio C Hamano
2022-07-10  1:33   ` [PATCH v3] " Junio C Hamano
2022-07-18 20:30     ` Derrick Stolee
2022-07-07 12:11 ` [PATCH] builtin/mv.c: use correct type to compute size of an array element Ævar Arnfjörð Bjarmason
2022-07-07 18:10   ` Junio C Hamano
2022-07-07 19:11     ` René Scharfe
2022-07-09  8:16       ` René Scharfe
2022-07-10  5:38         ` Junio C Hamano
2022-07-10 10:05           ` [PATCH] cocci: avoid normalization rules for memcpy René Scharfe
2022-07-10 14:45             ` Ævar Arnfjörð Bjarmason
2022-07-10 16:32               ` Ævar Arnfjörð Bjarmason
2022-07-10 19:30               ` Junio C Hamano
2022-07-11 17:11               ` René Scharfe
2022-07-11 20:05                 ` Ævar Arnfjörð Bjarmason
2022-07-07 18:27   ` [PATCH] builtin/mv.c: use correct type to compute size of an array element René Scharfe
2022-07-07 18:42 ` Jeff King
2022-07-07 20:25   ` Junio C Hamano [this message]

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