Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]
Groups > comp.lang.c > #101402
| 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: standard error codes |
| Date | Tue, 10 Jan 2017 13:00:02 -0800 |
| Organization | None to speak of |
| Lines | 36 |
| Message-ID | <ln37gqr5pp.fsf@kst-u.example.com> (permalink) |
| References | <96e16709-18eb-4399-86c4-a6f30a767df3@googlegroups.com> <212f08fd-b09e-4848-8485-f7480eaaae45@googlegroups.com> <bf564370-cac4-4030-8487-893c5ea71ddc@googlegroups.com> <86260b21-0fa2-42b4-93c6-08e9241d4c17@googlegroups.com> <lnk2a4qi1v.fsf@kst-u.example.com> <64011b84-2f8d-44f2-902a-0eacfcdf630b@googlegroups.com> <o510fi$16v$1@dont-email.me> <o51362$bse$1@dont-email.me> <11823fb6-613e-4283-95e8-dd930e152418@googlegroups.com> <o516ss$qp2$1@dont-email.me> <546841f1-b478-44dc-abc0-22ca4f46e553@googlegroups.com> <o51dsp$eb6$1@dont-email.me> <lnfukqrghw.fsf@kst-u.example.com> <o5387t$vp5$1@dont-email.me> <ln7f62r7xp.fsf@kst-u.example.com> <o53gf8$ls$1@dont-email.me> |
| Mime-Version | 1.0 |
| Content-Type | text/plain; charset=us-ascii |
| Injection-Info | mx02.eternal-september.org; posting-host="051d99dd7a883013689f38e075ee6474"; logging-data="22461"; mail-complaints-to="abuse@eternal-september.org"; posting-account="U2FsdGVkX1+2cOkrvtziLFxtRA/l76cb" |
| User-Agent | Gnus/5.13 (Gnus v5.13) Emacs/23.1 (gnu/linux) |
| Cancel-Lock | sha1:AXgGVSJG7JqO+MopzKuUc7TDcWE= sha1:hFfQfTv/cNEMbsLS4mGUcntD1EQ= |
| Xref | csiph.com comp.lang.c:101402 |
Show key headers only | View raw
BartC <bc@freeuk.com> writes:
> On 10/01/2017 20:12, Keith Thompson wrote:
>> BartC <bc@freeuk.com> writes:
>
>>> In that case it would be difficult to call, if getting a 1/0 result
>>> means an extra instruction instead of just returning the result of a
>>> subtraction.
>>
>> No, it's not difficult to call.
>
> I mean it's difficult to predict which would be faster; returning 0 or 1
> (which is more elegant and matches how a million other functions work),
> or returning some random result which has to be compared against zero.
If a function returns 0 or 1, that result still has to be compared
against zero.
Sure, it's difficult to predict. It shouldn't be difficult to
measure. Without such a measurement, I see no reason to spend
any time considering adding memeq() or streq() functions when the
existing memcmp() and strcmp() functions work just fine.
If you're concerned about performance, show some numbers. If you're
concerned about elegance:
#define MEMEQ(s1, s2, n) (memcmp((s1), (s2), (n)) == 0)
#define STREQ(s1, s2) (strcmp((s1), (s2)) == 0)
(I'm not certain that the parentheses around the argument names are
necessary, but better safe than sorry.)
--
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"
Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread
standard error codes Thiago Adams <thiago.adams@gmail.com> - 2017-01-08 06:34 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-08 11:05 -0800
Re: standard error codes Thiago Adams <thiago.adams@gmail.com> - 2017-01-09 03:33 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-09 04:55 -0800
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-09 09:06 -0800
Re: standard error codes Thiago Adams <thiago.adams@gmail.com> - 2017-01-09 09:52 -0800
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-09 21:50 +0000
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-09 22:36 +0000
Re: standard error codes supercat@casperkitty.com - 2017-01-09 14:51 -0800
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-09 23:39 +0000
Re: standard error codes supercat@casperkitty.com - 2017-01-09 15:51 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-09 16:08 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-09 18:51 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-10 02:02 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-10 07:34 -0800
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-10 01:39 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-10 09:07 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-10 09:59 -0800
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-10 12:02 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-10 12:53 -0800
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-10 13:03 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-10 15:41 -0800
Re: standard error codes Ben Bacarisse <ben.usenet@bsb.me.uk> - 2017-01-11 02:56 +0000
Re: standard error codes supercat@casperkitty.com - 2017-01-11 07:42 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-10 12:59 -0800
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-10 18:14 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-10 12:12 -0800
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-10 20:35 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-10 13:00 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-11 08:16 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-11 18:25 +0000
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-11 19:09 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-11 12:03 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-11 20:10 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-11 12:19 -0800
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-11 20:31 +0000
Re: standard error codes Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2017-01-11 15:32 -0500
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-11 20:48 +0000
Re: standard error codes Lew Pitcher <lew.pitcher@digitalfreehold.ca> - 2017-01-11 15:58 -0500
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-11 13:01 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-11 21:05 +0000
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-11 21:08 +0000
Re: standard error codes Gareth Owen <gwowen@gmail.com> - 2017-01-11 21:38 +0000
Re: standard error codes BartC <bc@freeuk.com> - 2017-01-11 21:58 +0000
Re: standard error codes David Brown <david.brown@hesbynett.no> - 2017-01-12 12:11 +0100
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-12 09:28 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-12 18:06 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-12 11:39 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-12 19:50 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-12 13:03 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-12 21:13 +0000
Re: standard error codes <william@wilbur.25thandClement.com> - 2017-01-12 20:00 -0800
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-13 01:56 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-13 12:54 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-13 09:35 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-13 17:38 +0000
Re: standard error codes James Kuyper <jameskuyper@verizon.net> - 2017-01-13 13:06 -0500
Re: standard error codes raltbos@xs4all.nl (Richard Bos) - 2017-01-18 12:00 +0000
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-18 12:13 +0000
Re: standard error codes Malcolm McLean <malcolm.mclean5@btinternet.com> - 2017-01-12 16:43 -0800
Re: standard error codes <william@wilbur.25thandClement.com> - 2017-01-12 19:34 -0800
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-13 09:27 -0800
Re: standard error codes raltbos@xs4all.nl (Richard Bos) - 2017-01-12 19:33 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-12 12:10 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-11 11:50 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-11 20:38 +0000
Re: standard error codes jadill33@gmail.com - 2017-01-11 12:26 -0800
Re: standard error codes Richard Heathfield <rjh@cpax.org.uk> - 2017-01-11 20:44 +0000
Re: standard error codes Keith Thompson <kst-u@mib.org> - 2017-01-09 09:03 -0800
Re: standard error codes supercat@casperkitty.com - 2017-01-08 11:40 -0800
csiph-web