Path: csiph.com!eternal-september.org!feeder.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Keith Thompson <kst-u@mib.org>
Newsgroups: comp.lang.c
Subject: Re: Optimizing the code: way to reduce if, else if-s within the loop?
Date: Sun, 22 Jan 2017 07:47:10 -0800
Organization: None to speak of
Lines: 21
Message-ID: <lnlgu3f669.fsf@kst-u.example.com>
References: <a7575c18-3cd0-427c-bfc3-0285b5770cb6@googlegroups.com> <pl678c5imu0sajbmj8lejvlik9hm1snkcg@4ax.com> <35c56d5c-ff4a-46b5-9166-e88353bf62ce@googlegroups.com> <o62392$ho0$1@dont-email.me> <o6256j$nou$1@dont-email.me> <87efzvxm7h.fsf@bsb.me.uk> <o62bvj$ma5$1@dont-email.me>
Mime-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Injection-Info: mx02.eternal-september.org; posting-host="888facdcfaaf0dacdc56e3b90fcf0c54"; logging-data="24027"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1/bzArm8BIPqZkiHDCUSBON"
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux)
Cancel-Lock: sha1:u80HBHbl0xAMa0Ysl5HBHglnUvE= sha1:9sDD+kF9HPt6iXjCKzGmF09gpsE=
Xref: csiph.com comp.lang.c:102327

BartC <bc@freeuk.com> writes:
> On 22/01/2017 13:23, Ben Bacarisse wrote:
>> BartC <bc@freeuk.com> writes:
[...]
>>> This seems a common way of implementing it:
>>>
>>> #define offsetof(s,m) (int)&(((s *)0)->m)
>>
>> That would be wrong so I'm sorry to hear it's a common way.
>
> What's wrong with it?

offsetof yields a result of type size_t.  This macro yields a result of
type int.  (It's also non-portable, but in a way that's likely to work
under most implementations.)

-- 
Keith Thompson (The_Other_Keith) kst-u@mib.org  <http://www.ghoti.net/~kst>
Working, but not speaking, for JetHead Development, Inc.
"We must do something.  This is something.  Therefore, we must do this."
    -- Antony Jay and Jonathan Lynn, "Yes Minister"