Path: ...!news.mixmin.net!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: James Kuyper <jameskuyper@alumni.caltech.edu>
Newsgroups: comp.lang.c
Subject: Re: how cast works?
Date: Fri, 9 Aug 2024 18:29:02 -0400
Organization: A noiseless patient Spider
Lines: 43
Message-ID: <v96580$788h$1@dont-email.me>
References: <v8vlo9$2oc1v$1@dont-email.me> <slrnvb7kis.28a.dan@djph.net>
 <v929ah$3u7l7$1@dont-email.me> <87ttfu94yv.fsf@nosuchdomain.example.com>
 <v93a3t$6q7v$1@dont-email.me> <v93e2q$8put$1@dont-email.me>
 <87bk228uzg.fsf@nosuchdomain.example.com> <v94pji$m1ib$1@dont-email.me>
 <v95lb7$26koh$1@dont-email.me> <v96000$3fvsp$2@dont-email.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Injection-Date: Sat, 10 Aug 2024 00:29:20 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="5da9026e4edcec1e1deb82f9c3783d4d";
	logging-data="237841"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX19VKsV2QJTDy8xOS5LD3jhp1oFs3k2s6XQ="
User-Agent: Mozilla Thunderbird
Cancel-Lock: sha1:Ni+GD35jmEjCvwVL+96l1lXwjW4=
Content-Language: en-US
In-Reply-To: <v96000$3fvsp$2@dont-email.me>
Bytes: 3051

Bart <bc@freeuk.com> writes:
> On 09/08/2024 18:57, James Kuyper wrote:
....
>> A cast is a piece of syntax that is used to explicitly request that
>> a
>> conversion be performed. Conversions that are explicitly requested in C
>> code are referred to as casts only by people who don't understand what
>> they're saying - the standard never refers to them as such.
>
> Are you sure? What else would they be known as?

As Keith said, that's a typo - the second "explicitly" should have been
"implicitly".

[...]
> Here it uses the term 'explicit cast'. Why is that; isn't the term
> 'cast' unambiguous without needing to say 'explicit'?

It's redundant, and occurs only once in the entire standard. The purpose
of that redundancy was to emphasize that what the conversion it
describes never happens implicitly (unlike many of the other conversions).

> Also, what is exactly is the difference between 'explicit conversion'
> and 'explicit cast'?

None

> Why can't there also be a similar correlation between 'implicit
> conversion' and 'implicit cast'?

The C standard defines "implicit conversion" and "explicit conversion"
in 6.3p1, and the definition it provides for "explicit conversion" is
"those [conversions] that result from a cast operation". it provides a
grammar production for a cast expression, and none for a implicit cast
expression.

> even if it did, surely people ought to be allowed to use alternate
> terms for an informal discussion? This is a not a committee meeting.

Every time you use a term with a standard-define meaning in a way that
doesn't match the meaning defined for it by the standard, you create
potential confusion. If that's what you want to do, go ahead, but it
seems an odd thing to do.