Path: ...!3.eu.feeder.erje.net!feeder.erje.net!news.in-chemnitz.de!news.swapon.de!eternal-september.org!feeder3.eternal-september.org!news.eternal-september.org!.POSTED!not-for-mail
From: Ben Bacarisse <ben@bsb.me.uk>
Newsgroups: comp.lang.c
Subject: Re: technology discussion =?utf-8?Q?=E2=86=92?= does the world need
 a "new" C ?
Date: Tue, 09 Jul 2024 18:22:56 +0100
Organization: A noiseless patient Spider
Lines: 47
Message-ID: <871q42qy33.fsf@bsb.me.uk>
References: <v66eci$2qeee$1@dont-email.me> <v67gt1$2vq6a$2@dont-email.me>
	<v687h2$36i6p$1@dont-email.me>
	<871q48w98e.fsf@nosuchdomain.example.com>
	<v68dsm$37sg2$1@dont-email.me>
	<87wmlzvfqp.fsf@nosuchdomain.example.com>
	<v6ard1$3ngh6$4@dont-email.me> <v6b0jv$3nnt6$1@dont-email.me>
	<87h6d2uox5.fsf@nosuchdomain.example.com>
	<v6d779$6rk5$2@dont-email.me> <v6e76u$c0i9$1@dont-email.me>
	<v6esqm$fian$2@dont-email.me> <v6f7vg$hgam$1@dont-email.me>
	<20240707164747.258@kylheku.com> <v6gl83$s72a$1@dont-email.me>
	<v6h8ao$ur1v$1@dont-email.me> <v6jhk3$1drd6$1@dont-email.me>
	<v6jiud$1dsjb$1@dont-email.me> <877cdur1z9.fsf@bsb.me.uk>
	<v6joi4$1epoj$1@dont-email.me>
MIME-Version: 1.0
Content-Type: text/plain
Injection-Date: Tue, 09 Jul 2024 19:22:57 +0200 (CEST)
Injection-Info: dont-email.me; posting-host="3bc602097df9bef4fe534cf857153f79";
	logging-data="1549294"; mail-complaints-to="abuse@eternal-september.org";	posting-account="U2FsdGVkX1+cu/h2EOvI3HyALLykR9+mHv3wIsV65ZQ="
User-Agent: Gnus/5.13 (Gnus v5.13)
Cancel-Lock: sha1:aHGDxRwqrvCa+YFCp0wPDfGWISA=
	sha1:b5Vma1BE6wKTxxHKeakwbvxZyj4=
X-BSB-Auth: 1.84ebe6aa0a370da19479.20240709182256BST.871q42qy33.fsf@bsb.me.uk
Bytes: 3417

bart <bc@freeuk.com> writes:

> On 09/07/2024 16:58, Ben Bacarisse wrote:
>> bart <bc@freeuk.com> writes:
>> 
>>> Arrays are passed by reference:
>>>
>>>    void F(int a[20]) {}
>>>
>>>    int main(void) {
>>>      int x[20];
>>>      F(x);
>>>    }
>> This is the sort of thing that bad tutors say to students so that they
>> never learn C properly.  All parameter passing in C is by value.  All of
>> it.  You just have to know (a) what the syntax means and (b) what values
>> get passed.
>
> The end result is that a parameter declared with value-array syntax is
> passed using a reference rather than by value.
>
> And it does so because the language says, not because the ABI requires
> it. A 2-byte array is also passed by reference.

An address value is passed by value.  C has only one parameter passing
mechanism.  You can spin it as much as you like, but C's parameter
passing is simple to understand, provided learner tune out voices like
yours.

>> void F(int a[20]) ... declares a to be of type int *.  Feel free to rail
>> about that as much as you like but that is what that syntax means.
>> The x in F(x) is converted to a pointer to x[0] since the x is not an
>> operand of &, sizeof etc.  F(x) passes a pointer by value.  F receives a
>> pointer value in a.
>> 
>>> Although the type of 'a' inside 'F' will be int* rather than
>>> int(*)[20].
>> No.  a is of type int *.
>
> And that is different 'int*' how, about from having an extra space which C
> says is not signigicant in this context?

Sorry, I missed what you wrote.  I don't know why even brought up int
(*)[20] but I thought you were saying that was the type of a.

-- 
Ben.