lkml.org 
[lkml]   [2004]   [Sep]   [26]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 8/10] Re: [2.6-BK-URL] NTFS: 2.1.19 sparse annotation, cleanups and a bugfix
On Sat, 25 Sep 2004, Linus Torvalds wrote:
> I personally believe that people use enum's largely in two (independent)
> ways:
>
> - a convenient compile-time constant:
>
> enum {
> DevEnableMask = 1UL << 0,
> DevIRQMask = 1UL << 5,
> DevError = 1UL << 31
> };
>
> where you never actually _save_ an enum anywhere. In this case, the
> typing is very convenient indeed.
>
> - a "type enumerator":
>
> enum token_type {
> TOKEN_IDENT = 1,
> TOKEN_NUMBER,
> TOKEN_MACRO,
> ...
>
> where the enum actually is used as a variable to distinguish different
> cases. In this case, the per-enum typing ends up being possibly even
> confusing, since using a constant will have a potentially _different_
> type than loading that constant from a variable.
>
> The second case is why I think it's a sane thing to warn if anybody ever
> creates a variable (or structure/union member) with an enum that used the
> typing features. Not because we can't make the enum fit all the values,
> but because the types simply WILL NOT MATCH. They fundamentally cannot,
> since we took the approach of having per-entry types.
>
> And for sparse, since the type is _the_ most important part of anything,
> we should warn when the types won't match.

What does sparse do at the moment when the enum size has been changed
away from sizeof(int) using __attribute__ ((__packed__))?

Best regards,

Anton
--
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK
Linux NTFS maintainer / IRC: #ntfs on irc.freenode.net
WWW: http://linux-ntfs.sf.net/ & http://www-stu.christs.cam.ac.uk/~aia21/
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 14:06    [W:0.046 / U:0.336 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site