Re: How to get isblank?

[Eric Blake]

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According to Bruno Haible on 10/6/2009 3:15 PM:
>> Sorry if I'm being dense, but perhaps there's an opportunity for
>> clarification here?
> 
> The relevant documentation in gnulib for this function is in the file
> doc/posix-functions/isblank.texi:
> 
> The reasons include:
> 
>   1) No one asked for it so far.
> 
>   2) On all known platforms, in all predefined locales, isblank(c) is likely
>      equivalent with  (c == ' ' || c == '\t').  Look at the glibc definition
>      (in glibc/localedata/locales/i18n): The "blank" characters are
>      '\t', ' ', U+1680, U+180E, U+2000..U+2006, U+2008..U+200A, U+205F, 
> U+3000,
>      and none except the two is present in a common 8-bit encoding.
> 
> So instead of using this function, with platform dependent semantics, most
> programs will either want the pure ASCII version (c_isblank) or the Unicode
> aware version (uc_is_blank).

Can we add a summary of this logic to the isblank.texi documentation, to
point people to better replacements?

- --
Don't work too hard, make some time for fun as well!

Eric Blake             address@hidden
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