Re: new module mbrtoc32-regular

[Paul Eggert]

On 2023-07-10 15:45, Bruno Haible wrote:
> DEFINITION: We call an mbrtoc32 function_regular_  if
>    - It never returns (size_t)-3.
>    - When it returns < (size_t)-2, the mbstate_t is in the initial state.

"the initial state" -> "an initial state". But even with that change 
isn't the second part of this definition a bit too strict? Even if 
mbsinit returns nonzero, things are still OK if further scanning behaves 
as if the mbstate_t were all zero. Although this implementation behavior 
would be silly, POSIX doesn't prohibit it, and it would suffice for 
mbcel and should suffice for similar uses.

That being said, I think the newly-added test-mbrtoc32-regular.c, which 
uses mbrinit, is OK, as it should pass on all practical platforms. If an 
oddball platform ever comes up we can worry about it then.


> +#  if GNULIB_MBRTOC32_REGULAR
> +  /* Verify that mbrtoc32 is regular.  */
> +  if (ret < (size_t) -3 && ! mbsinit (ps))
> +    /* This occurs on glibc 2.36.  */
> +    memset (ps, '\0', sizeof (mbstate_t));
> +  if (ret == (size_t) -3)
> +    abort ();
> +#  endif

Since this is inside mbrtoc32, performance is relevant, so shouldn't 
this be tested at configure-time instead of at run-time? That is, 
shouldn't the "#if" test be something more like "#if 
GNULIB_MBRTOC32_REGULAR && HAVE_MBRTOC32_RETURNS_MINUS_3", where 
GNULIB_MBRTOC32_RETURNS_MINUS_3 is zero on all known platforms?