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From: Silas McCroskey <inkswinc@gmail.com>
To: 9front@9front.org
Subject: Re: [9front] Mixfs: potential bug?
Date: Wed, 12 Feb 2020 16:21:04 -0800	[thread overview]
Message-ID: <CAHjwAuxsW9J2faquv2djaedf9fT9OgFXc6FRfBH29vQBaRm6fA@mail.gmail.com> (raw)
In-Reply-To: <1ba93b51-da78-8c37-f714-e354fab32b5a@qs.co.nz>

http://doc.cat-v.org/plan_9/4th_edition/papers/comp

The "Extensions" section goes over this compiler extension:

structs-within-structs declared without a name allow their members to
be accessed directly, so
qlock(s)
does the same thing as
qlock(s->Lock)
since the "locked" member used by qlock is accessible to both.

This is a compiler extension rather than pointer tricks, so it does
not depend on ordering within the struct (as displayed in the
Extensions section itself, where Lock is the last member of the outer
struct).

- sam-d

On Wed, Feb 12, 2020 at 4:07 PM Trevor Higgins
<plan9fullfrontal@qs.co.nz> wrote:
>
> Looking at the code for audio/mixfs (mixfs.c)
>
> The code uses qlock(s) where s is: struct Stream*.
>
> In the structure ,shouldn't the QLock member of the structure be the
> first member in the structure?
> If not so, then why does it not matter?
>
> Thanks.
>
> --
>


  reply	other threads:[~2020-02-13  0:21 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-12 20:51 Libpng and Zlib updates on the ports tree Lucas Francesco
2020-02-12 21:01 ` [9front] " ori
2020-02-13  0:06 ` Mixfs: potential bug? Trevor Higgins
2020-02-13  0:21   ` Silas McCroskey [this message]
2020-02-13  0:33     ` [9front] " Eli Cohen
2020-02-13  1:22     ` Trevor Higgins

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