On Thu, Jun 1, 2017 at 2:43 PM, Charles Mills <[email protected]> wrote:
> It's clearly doing everything in ASCII:
>
> strcasecmp("Z", "0") 122
>
> It's interesting. I use the same compare function for both a sort and for a
> binary search, so it all works correctly -- it's just not working the way I
> think it is.
>
> Charles
>
>
I'm not any kind of an expert on this. So take everything I say with about
a kilo of NaCl. As the pages you referenced states, the strcasecmp()
function is locale sensitive. The locale ordering is NOT based on the code
point (hex value) at all (well at least conceptually). It is based on the
"rune". Where "rune" is basically the concept of what character this is,
such as used in UNICODE (e.g. LATIN-SMALL-LETTER-A is 'a' regardless of the
hex value(s) used to store that in memory). For something "simple" you can
sort of think of the hex value as being an index into an array of values,
where the value at that index value is the relative collating position of
the "rune" involved in the comparison. This is how strcasecmp("A","a") is
"equal". The relative collating position of "A" and "a" are the same, so
the comparison is "equal".
Of course, it looks like it is an ASCII compare because the relative
positioning of the of the letters in the "C" (default) locale is pretty
much the same as the order of "ASCII" characters when looked at as plain 8
byte unsigned integers.
--
Windows. A funny name for a operating system that doesn't let you see
anything.
Maranatha! <><
John McKown
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