Re: technology discussion → does the world need a "new" C ?

Liste des GroupesRevenir à cl c 
Sujet : Re: technology discussion → does the world need a "new" C ?
De : bc (at) *nospam* freeuk.com (bart)
Groupes : comp.lang.c
Date : 10. Jul 2024, 00:04:40
Autres entêtes
Organisation : A noiseless patient Spider
Message-ID : <v6kfm6$1ier7$1@dont-email.me>
References : 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
User-Agent : Mozilla Thunderbird
On 09/07/2024 23:32, Kaz Kylheku wrote:
On 2024-07-09, bart <bc@freeuk.com> wrote:
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.
 In C, arrays are not passed to functions, period.
Arrays can be passed by explicit reference:
   void F(int(*A)[20]) {
       printf("%zu\n", sizeof(*A)/sizeof((*A)[0]));    // shows 20
   }
That can be called like this:
   int a[20];
   F(&a);
Here, an actual array type is involved, which is passed by an actual pointer to array, not a pointer to its elements.

Therefore ABIs do not say anything about array parameters,
(or if they do, it's not in relation to C).
That makes a change; most people think that C invented ABIs, which were created in its image.
The Win64 ABI talks about aggregate types.

Date Sujet#  Auteur
5 Jul 24 * Re: technology discussion → does the world need a "new" C ?306Lawrence D'Oliveiro
5 Jul 24 `* Re: technology discussion → does the world need a "new" C ?305BGB
5 Jul 24  +* Re: technology discussion → does the world need a "new" C ?2Lawrence D'Oliveiro
5 Jul 24  i`- Re: technology discussion → does the world need a "new" C ?1yeti
5 Jul 24  +* Re: technology discussion → does the world need a "new" C ?275Keith Thompson
5 Jul 24  i+- Re: technology discussion → does the world need a "new" C ?1Lawrence D'Oliveiro
15 Jul 25  i`- 
5 Jul 24  +* Re: technology discussion → does the world need a "new" C ?26bart
5 Jul 24  i+- Re: technology discussion → does the world need a "new" C ?1BGB
6 Jul 24  i`* Re: technology discussion → does the world need a "new" C ?24Lawrence D'Oliveiro
6 Jul 24  i +* Re: technology discussion → does the world need a "new" C ?17Keith Thompson
6 Jul 24  i i+- Re: technology discussion → does the world need a "new" C ?1Janis Papanagnou
6 Jul 24  i i`* Re: technology discussion → does the world need a "new" C ?15Lawrence D'Oliveiro
6 Jul 24  i i +- Re: technology discussion → does the world need a "new" C ?1Ben Bacarisse
6 Jul 24  i i +- Re: technology discussion → does the world need a "new" C ?1Keith Thompson
7 Jul 24  i i +* Re: technology discussion → does the world need a "new" C ?10James Kuyper
10 Jul 24  i i i`* Re: technology discussion → does the world need a "new" C ?9Lawrence D'Oliveiro
10 Jul 24  i i i `* Re: technology discussion → does the world need a "new" C ?8James Kuyper
11 Jul 24  i i i  `* Re: technology discussion → does the world need a "new" C ?7Lawrence D'Oliveiro
11 Jul 24  i i i   +* Re: technology discussion → does the world need a "new" C ?2David Brown
11 Jul 24  i i i   i`- Re: technology discussion → does the world need a "new" C ?1Malcolm McLean
11 Jul 24  i i i   +* Re: technology discussion → does the world need a "new" C ?3bart
11 Jul 24  i i i   i`* Re: technology discussion → does the world need a "new" C ?2Chris M. Thomasson
12 Jul 24  i i i   i `- Re: technology discussion → does the world need a "new" C ?1Chris M. Thomasson
11 Jul 24  i i i   `- Re: technology discussion → does the world need a "new" C ?1James Kuyper
7 Jul 24  i i +- Re: technology discussion → does the world need a "new" C ?1Tim Rentsch
25 Aug 24  i i `- Re: technology discussion ? does the world need a "new" C ?1dave thompson 2
6 Jul 24  i +- Re: technology discussion → does the world need a "new" C ?1Janis Papanagnou
6 Jul 24  i +- Re: technology discussion → does the world need a "new" C ?1James Kuyper
6 Jul 24  i `* Re: technology discussion → does the world need a "new" C ?4bart
7 Jul 24  i  `* Re: technology discussion → does the world need a "new" C ?3Keith Thompson
7 Jul 24  i   `* Re: technology discussion → does the world need a "new" C ?2bart
7 Jul 24  i    `- Re: technology discussion → does the world need a "new" C ?1Keith Thompson
5 Jul 24  `- Re: technology discussion → does the world need a "new" C ?1lexi hale

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