Re: enum vs int and API/ABI compatibility

[Bruno Haible]

Simon Josefsson asked:
> > 2) Change the argument type of idna_strerror to 'int'.
> > Change the enum from
> >
> >      typedef enum {
> >        ...
> >        IDNA_ICONV_ERROR = 9,
> >        ...
> >      } Idna_rc;
> >
> >    to
> >
> >      typedef int Idna_rc;
> >      #ifdef __cplusplus
> >      /* In C++ we avoid macros.  */
> >      ...
> >      const int IDNA_ICONV_ERROR = 9;
> >      ...
> >      #else
> >      ...
> >      #define IDNA_ICONV_ERROR 9
> >      ...
> >      #endif
> 
> Why is this second part needed?

It is in fact not needed (cf. ISO C99 section 6.7.2.2.(3)). You can also
write

     typedef int Idna_rc;
     #ifdef __cplusplus
     ...
     const int IDNA_ICONV_ERROR = 9;
     ...
     #else
     enum {
     ...
     IDNA_ICONV_ERROR = 9,
     ...
     };
     #endif

Bruno
-- 
In memoriam Eduard Brücklmeier <http://en.wikipedia.org/wiki/Eduard_Brücklmeier>