From: Denis Vlasenko <vda@ilport.com.ua>
To: Coywolf Qi Hunt <coywolf@gmail.com>
Subject: Re: Use enum to declare errno values
Date: Fri, 2 Dec 2005 15:20:52 +0200
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Cc: Pekka Enberg <penberg@cs.helsinki.fi>,
       "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 14:56, Coywolf Qi Hunt wrote:
> 2005/12/2, Pekka Enberg <penberg@cs.helsinki.fi>:
> > Hi,
> >
> > 2005/12/2, Denis Vlasenko <vda@ilport.com.ua>:
> > > > There is another reason why enums are better than #defines:
> >
> > On 12/2/05, Coywolf Qi Hunt <coywolf@gmail.com> wrote:
> > > This is a reason why enums are worse than #defines.
> > >
> > > Unlike in other languages, C enum is not much useful in practices.
> > > Maybe the designer wanted C to be as fancy as other languages?  C
> > > shouldn't have had enum imho. Anyway we don't have any strong motives
> > > to switch to enums.
> >
> > I don't follow your reasoning. The naming collision is a real problem
> > with macros. With enum and const, the compiler can do proper checking
> > with meaningful error messages. Please explain why you think #define
> > is better for Denis' example?
> >
> >                                      Pekka
> 
> That is a bad bad style. It should be `#define FOO 123' if you have to
> write it.

I suspect this style was invented exactly as a device to stop confusing
macro names with variable/function names.

> It's also hard to see what the confusing bar is "if you are looking at
> file.c alone".

int f(int foo, int bar) {...}

bar is a parameter of type "int" of function f(). What else it could be here?
It's basic C.

> 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.
> 
> Macros play an important role in C, but enums don't.

Looks more like your personal dislike to enum keyword.
--
vda
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