Re: Use enum to declare errno values

[Coywolf Qi Hunt]

2005/12/2, Denis Vlasenko <vda@xxxxxxxxxxxxx>:
> On Thursday 01 December 2005 22:01, linux-os (Dick Johnson) wrote:
> > On Thu, 24 Nov 2005, Paul Jackson wrote:
> >
> > > If errno's were an enum type, what would be the type
> > > of the return value of a variety of kernel routines
> > > that now return an int, returning negative errno's on
> > > error and zero or positive values on success?
> >
> > enums are 'integer types', one of the reasons why #defines
> > which are also 'integer types' are just as useful. If you
> > want to auto-increment these integer types, then enums are
> > useful. Otherwise, just use definitions.
>
> There is another reason why enums are better than #defines:

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.

>
> file.h:
> #define foo 123
> enum {
>         bar = 123
> };
>
>
> file.c:
> ...
> #include "something_which_eventually_includes_file.h"
> ...
> int f(int foo, int bar)
> {
>         return foo+bar;
> }
>
> Above program has compile-time bug, but it's rather hard
> to see it if you are looking at file.c alone.
> --
> vda
--
Coywolf Qi Hunt
http://sosdg.org/~coywolf/
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