Re: Use enum to declare errno values

[Bill Davidsen <davidsen@tmr.com>]

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.
> 
> 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@tmr.com>
   CTO TMR Associates, Inc
   Doing interesting things with small computers since 1979