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From: "René Scharfe" <l.s.r@web.de>
To: Jeff King <peff@peff.net>
Cc: Vegard Nossum <vegard.nossum@oracle.com>,
	Lars Schneider <larsxschneider@gmail.com>,
	Junio C Hamano <gitster@pobox.com>,
	allan.x.xavier@oracle.com,
	Johannes Schindelin <Johannes.Schindelin@gmx.de>,
	Git List <git@vger.kernel.org>
Subject: Re: [PATCH v1] Travis: also test on 32-bit Linux
Date: Fri, 10 Mar 2017 17:20:13 +0100	[thread overview]
Message-ID: <04f4849c-e1e0-f0ac-5b1e-10a343391db4@web.de> (raw)
In-Reply-To: <20170310081759.yka476hnw4w3mghs@sigill.intra.peff.net>

Am 10.03.2017 um 09:18 schrieb Jeff King:
> On Fri, Mar 10, 2017 at 01:14:16AM +0100, René Scharfe wrote:
>
>>>   2. Ones which just copy a single object, like:
>>>
>>>        memcpy(&dst, &src, sizeof(dst));
>>>
>>>      Perhaps we should be using struct assignment like:
>>>
>>>        dst = src;
>>>
>>>      here. It's safer and it should give the compiler more room to
>>>      optimize. The only downside is that if you have pointers, it is
>>>      easy to write "dst = src" when you meant "*dst = *src".
>>
>> Compilers can usually inline memcpy(3) calls, but assignments are
>> shorter and more pleasing to the eye, and we get a type check for
>> free.  How about this?
>
> Yeah, I mostly wasn't sure how people felt about "shorter and more
> pleasing". It _is_ shorter and there's less to get wrong. But the
> memcpy() screams "hey, I am making a copy" and is idiomatic to at least
> a certain generation of C programmers.
>
> I guess something like COPY(dst, src) removes the part that you can get
> wrong, while still screaming copy. It's not idiomatic either, but at
> least it stands out. I dunno.

Yes ...

> I think this misses the other two cases: (*dst, src) and (*dst, *src).

... and that's why I left them out.  You can't get dst vs. *dst wrong 
with structs (at least not without the compiler complaining); only safe 
transformations are included in this round.

René

  reply	other threads:[~2017-03-10 16:20 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-02-28 19:17 [PATCH] Travis: also test on 32-bit Linux Johannes Schindelin
2017-02-28 20:34 ` Johannes Schindelin
2017-03-02  5:06 ` Junio C Hamano
2017-03-02 10:51 ` [PATCH v1] " Lars Schneider
2017-03-02 11:24   ` Johannes Schindelin
2017-03-02 11:38     ` Lars Schneider
2017-03-02 14:22       ` Johannes Schindelin
2017-03-02 15:53         ` Christian Couder
2017-03-02 18:03       ` Junio C Hamano
2017-03-03  2:17         ` Johannes Schindelin
2017-03-03 18:43           ` Junio C Hamano
2017-03-04  0:03             ` Junio C Hamano
2017-03-04  4:11               ` Junio C Hamano
2017-03-04 17:23                 ` Lars Schneider
2017-03-04 18:08                   ` Vegard Nossum
2017-03-04 19:49                     ` Vegard Nossum
2017-03-04 20:08                       ` Vegard Nossum
2017-03-05 11:36                         ` Jeff King
2017-03-05 11:44                           ` [PATCH] line-log: use COPY_ARRAY to fix mis-sized memcpy Jeff King
2017-03-05 12:20                             ` Vegard Nossum
2017-03-05 11:46                           ` [PATCH v1] Travis: also test on 32-bit Linux Jeff King
2017-03-10  0:14                           ` René Scharfe
2017-03-10  8:18                             ` Jeff King
2017-03-10 16:20                               ` René Scharfe [this message]
2017-03-10 17:57                                 ` Jeff King
2017-03-10 18:31                                   ` René Scharfe
2017-03-10 20:13                                 ` Junio C Hamano
2017-03-10 20:18                                   ` Jeff King
2017-03-10 22:04                                   ` René Scharfe
2017-03-10 23:33                                     ` Junio C Hamano
2017-03-11 14:17                                       ` René Scharfe
2017-03-10  0:14                           ` René Scharfe
2017-03-10  7:45                             ` Jeff King
2017-03-02 15:17     ` Ramsay Jones
2017-03-05 17:38       ` Lars Schneider
2017-03-05 22:16         ` Ramsay Jones

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