Re: [PATCH 1/5] maint: ensure that MB_CUR_MAX is defined even when !MBS_SUPPORT

[Jim Meyering]

Paul Eggert wrote:

> On 10/10/11 01:03, Paolo Bonzini wrote:
>
>> The reason is that then MB_CUR_MAX would be inconsistent with the
>> behavior of mbrlen and similar functions.
>
> Surely it's OK if MB_CUR_MAX is larger than it strictly needs to be.
> I can't think of any application that would break if MB_CUR_MAX
> were set to MB_LEN_MAX on ancient hosts that lacked MB_CUR_MAX.

I agree.

Remember the code we're talking about here (from src/mbsupport.h):

    #if defined HAVE_WCSCOLL && defined HAVE_ISWCTYPE
    # define MBS_SUPPORT 1
    #else
    # define MBS_SUPPORT 0
    #endif

    #if ! MBS_SUPPORT
    # undef MB_CUR_MAX
    # define MB_CUR_MAX 1
    #endif

That #undef is used only on relatively old systems that lack the
required support.  And with MBS_SUPPORT/MB_CUR_MAX == 0/1, uses
of multi-byte functions like mbrlen should be #if'd or compiled out.

Without an actual failure (or at least a more plausible argument),
adding a symbol like GREP_MB_CUR_MAX feels unjustified.