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From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: Thu, 11 Apr 2024 09:30:31 +0200
Message-ID: <CAMuHMdX_n4kifH6F20tt-umtL3rY9zb6=XmgrnXvuOJSibhrEQ@mail.gmail.com>
Subject: Re: [PATCH v1 2/2] auxdisplay: charlcd: Provide a forward declaration
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: linux-kernel@vger.kernel.org, Andy Shevchenko <andy@kernel.org>
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Hi Andy,

On Tue, Apr 9, 2024 at 6:15=E2=80=AFPM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
> While there is no compilation error, strictly speaking compiler
> should know about used types beforehand. Provide a forward decoration

declaration

> for struct charlcd_ops before using it in struct charlcd.
>
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

> --- a/drivers/auxdisplay/charlcd.h
> +++ b/drivers/auxdisplay/charlcd.h
> @@ -36,6 +36,8 @@ enum charlcd_lines {
>         CHARLCD_LINES_2,
>  };
>
> +struct charlcd_ops;
> +
>  struct charlcd {
>         const struct charlcd_ops *ops;

No forward declaration is needed at this point, as ops is a _pointer_ to
the structure.

>         const unsigned char *char_conv; /* Optional */

Gr{oetje,eeting}s,

                        Geert

--=20
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k=
org

In personal conversations with technical people, I call myself a hacker. Bu=
t
when I'm talking to journalists I just say "programmer" or something like t=
hat.
                                -- Linus Torvalds