Re: [PATCH] Add !HAVE_MBRTOWC fallbacks for mbchar, mbiter and mbuiter

[Bruno Haible]

Eric Blake wrote:
> > There are probably two uses of the mbchar, mbfile, mbiter, mbuiter modules:
> >   (a) Use them only for MB_CUR_MAX > 1, and use simpler datatypes (just
> >       'char' and pointers) for MB_CUR_MAX = 1.
> >   (b) Use them always.
> 
> ... there are things to be aware of.  ...
> the code didn't  consistently stick with approach a) vs. b).

The macros I posted can often formulate the algorithm in such a way that it
can be instantiated twice: once for MB_CUR_MAX > 1, once for MB_CUR_MAX = 1,
_without_ code changes. In other words, if you write

  /* Instantiate the code for MB_CUR_MAX > 1. */
  #include "mbchar_multi.h"
  #include "my-code.h"
  #include "mbchar_undef.h"

  /* Instantiate the code for MB_CUR_MAX = 1. */
  #include "mbchar_8bit.h"
  #include "my-code.h"
  #include "mbchar_undef.h"

you get a multibyte version and a unibyte version of the code that are
consistent - because they share the same source code.

Bruno