linux-kernel - Re: [PATCH 2/2] system_data_types.7: void *: Add info about pointer artihmetic

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Message-ID: <71ccc433-a5e4-92a7-6f09-d809c64b63f0@gmail.com>
Date:   Fri, 2 Oct 2020 11:46:28 +0200
From:   Alejandro Colomar <colomar.6.4.3@...il.com>
To:     mtk.manpages@...il.com, eggert@...ucla.edu, David.Laight@...LAB.COM
Cc:     linux-man@...r.kernel.org, gcc-patches@....gnu.org,
        libc-alpha@...rceware.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/2] system_data_types.7: void *: Add info about pointer
 artihmetic

Hi Michael,

The 2/2 is a typo.  This is a standalone patch.

Cheers,

Alex

On 2020-10-02 11:44, Alejandro Colomar wrote:
> Reported-by: Paul Eggert <eggert@...ucla.edu>
> Reported-by: David Laight <David.Laight@...LAB.COM>
> Signed-off-by: Alejandro Colomar <colomar.6.4.3@...il.com>
> ---
> 
> Paul and David,
> Thanks for your input!
> 
> Alex
> 
> 
>   man7/system_data_types.7 | 11 +++++++++++
>   1 file changed, 11 insertions(+)
> 
> diff --git a/man7/system_data_types.7 b/man7/system_data_types.7
> index 6451782db..bc7d5a8a0 100644
> --- a/man7/system_data_types.7
> +++ b/man7/system_data_types.7
> @@ -1918,6 +1918,17 @@ A value of this type can't be dereferenced,
>   as it would give a value of type
>   .I void
>   which is not possible.
> +Likewise, pointer arithmetic is not possible with this type.
> +However, in GNU C, poitner arithmetic is allowed
> +as an extension to the standard;
> +this is done by treating the size of a
> +.I void
> +or of a function as 1.
> +A consequence of this is that
> +.I sizeof
> +is also allowed on
> +.I void
> +and on function types, and returns 1.
>   .PP
>   The conversion specifier for
>   .I void *
>