Re: Use enum to declare errno values

[Bill Davidsen]

Coywolf Qi Hunt wrote:
> 2005/12/2, Pekka Enberg <penberg@xxxxxxxxxxxxxx>:
>
> > Hi,
> >
> > 2005/12/2, Denis Vlasenko <vda@xxxxxxxxxxxxx>:
> >
> > > > There is another reason why enums are better than #defines:
> >
> > On 12/2/05, Coywolf Qi Hunt <coywolf@xxxxxxxxx> 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.
>
> 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.

--
bill davidsen <davidsen@xxxxxxx>
  CTO TMR Associates, Inc
  Doing interesting things with small computers since 1979
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