From: Denis Vlasenko <vda@ilport.com.ua>
To: Vadim Lobanov <vlobanov@speakeasy.net>
Subject: Re: Use enum to declare errno values
Date: Sun, 4 Dec 2005 15:10:18 +0200
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Cc: Bill Davidsen <davidsen@tmr.com>, Coywolf Qi Hunt <coywolf@gmail.com>,
       "linux-os (Dick Johnson)" <linux-os@analogic.com>,
       Paul Jackson <pj@sgi.com>, francis_moreau2000@yahoo.fr,
       linux-kernel@vger.kernel.org
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On Friday 02 December 2005 18:56, Vadim Lobanov wrote:
> On Fri, 2 Dec 2005, Bill Davidsen wrote:
> 
> > Coywolf Qi Hunt wrote:
> > >
> > > That is a bad bad style. It should be `#define FOO 123' if you have to
> > > write it.
> > >
> > > It's also hard to see what the confusing bar is "if you are looking at
> > > file.c alone".
> > >
> > > enum is worse than typdef.  Don't you see why we should use `struct
> > > task_struct', rather than `task_t'?
> > >
> > > Introducing enum alone can't solve the problems from bad macro usage
> > > habits. Actually, it's not anything wrong with macros, it's
> > > programers' bad coding style.
> >
> > Using enum doesn't *solve* problems, it does *allow* type checking, and
> > *prevent* namespace pollution. Use of typedef allows future changes, if
> > you use "struct XXX" you're stuck with it.
> 
> You're not stuck with anything onerous in this case. Namely,
> 
> If you have "enum XXX" and you want to go to "enum YYY", then...
> 	sed 's/enum XXX/enum YYY/g'
> If you have "struct XXX" and you want to go to "struct YYY", then...
> 	sed 's/struct XXX/struct YYY/g'
> If you have "enum XXX" and you want to go to "struct YYY", then...
> This is a big change, and should be done with care anyway. If struct YYY
> happens to be large, then suddenly you can get all sorts of nifty stack
> overflows.

I was talking about _anonymous enums_. There you do not have enum XXX,
you have only named constants of type int:

enum { CONST = 12345 };

CONST is of type "int" here.
--
vda
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