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From: Keith Thompson <Keith.S.Thompson+u@gmail.com>
Newsgroups: comp.lang.c
Subject: Re: "undefined behavior"?
Date: Wed, 12 Jun 2024 15:18:34 -0700
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David Brown <david.brown@hesbynett.no> writes:
[...]
> I recommend never using "char" as a type unless you really mean a
> character, limited to 7-bit ASCII.  So if your "outliers" array really 
> is an array of such characters, "char" is fine.  If it is intended to
> be numbers and for some reason you specifically want 8-bit values, use 
> "uint8_t" or "int8_t", and initialise with { 0 }.
[...]

The implementation-definedness of plain char is awkward, but char
arrays generally work just fine for UTF-8 strings.  If char is
signed, byte values greater than 127 will be stored as negative
values, but it will almost certainly just work (if your system
is configured to handle UTF-8).  Likewise for Latin-1 and similar
8-bit character sets.

The standard string functions operate on arrays of plain char, so
storing UTF-8 strings in arrays of uint8_t or unsigned char will
seriously restrict what you can do with them.

(I'd like to a future standard require plain char to be unsigned,
but I don't know how likely that is.)

-- 
Keith Thompson (The_Other_Keith) Keith.S.Thompson+u@gmail.com
void Void(void) { Void(); } /* The recursive call of the void */