Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.c > #94719

Re: C language declaration "bugs"

Show all headers | View raw

Thiago Adams <thiago.adams@gmail.com> writes:

> On Tuesday, October 11, 2016 at 9:58:52 AM UTC-3, Ben Bacarisse wrote:
>> Thiago writes:
>
>> But now the []s in that position have acquired a new set of meanings:
>> 
>>   void f(int n, int a[n]);       // variably modified parameter
>
>
> void f(int n, int a[n]);
>
> This one is a tip? where n is the size?

Yes, because the "first level" of []s always just mean "pointer" so the
n is really only for documentary purposes.  A proper variably modified
array parameter would have []s where the size matters:

  void f(int n, int (*a)[n]);
  void f(int m, int n, int a[m][n]);

Note that the type of a is the same in both of the functions.  Here,
sizeof a will give the size of a pointer, but sizeof a[0] will depend on
n.

> I can't find any options to express dynamic arrays in structs.

No, you can't, other than the "struct hack" of putting a flexible array
member (i.e. an incomplete array declaration) as the last member.

<snip>
-- 
Ben.

Back to comp.lang.c | Previous | Next — Previous in thread | Next in thread | Find similar | Unroll thread

Thread

C language declaration "bugs" Thiago Adams <thiago.adams@gmail.com> - 2016-10-11 05:17 -0700
  Re: C language declaration "bugs" Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-10-11 13:58 +0100
    Re: C language declaration "bugs" Thiago Adams <thiago.adams@gmail.com> - 2016-10-11 06:47 -0700
      Re: C language declaration "bugs" Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-10-11 15:03 +0100
        Re: C language declaration "bugs" Thiago Adams <thiago.adams@gmail.com> - 2016-10-11 07:41 -0700
          Re: C language declaration "bugs" BartC <bc@freeuk.com> - 2016-10-11 16:31 +0100
        Re: C language declaration "bugs" Keith Thompson <kst-u@mib.org> - 2016-10-11 10:01 -0700
          Re: C language declaration "bugs" Ben Bacarisse <ben.usenet@bsb.me.uk> - 2016-10-11 19:10 +0100
  Re: C language declaration "bugs" BartC <bc@freeuk.com> - 2016-10-11 14:14 +0100

csiph-web