Re: Use enum to declare errno values

Coywolf Qi Hunt wrote:

2005/12/2, Pekka Enberg <[email protected]>:

Hi,

2005/12/2, Denis Vlasenko <[email protected]>:

There is another reason why enums are better than #defines:

On 12/2/05, Coywolf Qi Hunt <[email protected]> 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 <[email protected]>
  CTO TMR Associates, Inc
  Doing interesting things with small computers since 1979
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