/*
=for apidoc is_utf8_invariant_string
-Returns true iff the first C<len> bytes of the string C<s> are the same
+Returns TRUE if the first C<len> bytes of the string C<s> are the same
regardless of the UTF-8 encoding of the string (or UTF-EBCDIC encoding on
-EBCDIC machines). That is, if they are UTF-8 invariant. On ASCII-ish
-machines, all the ASCII characters and only the ASCII characters fit this
-definition. On EBCDIC machines, the ASCII-range characters are invariant, but
-so also are the C1 controls and C<\c?> (which isn't in the ASCII range on
-EBCDIC).
+EBCDIC machines); otherwise it returns FALSE. That is, it returns TRUE if they
+are UTF-8 invariant. On ASCII-ish machines, all the ASCII characters and only
+the ASCII characters fit this definition. On EBCDIC machines, the ASCII-range
+characters are invariant, but so also are the C1 controls.
If C<len> is 0, it will be calculated using C<strlen(s)>, (which means if you
use this option, that C<s> can't have embedded C<NUL> characters and has to
/*
=for apidoc is_utf8_string
-Returns true if the first C<len> bytes of string C<s> form a valid
-UTF-8 string, false otherwise. If C<len> is 0, it will be calculated
-using C<strlen(s)> (which means if you use this option, that C<s> can't have
-embedded C<NUL> characters and has to have a terminating C<NUL> byte). Note
-that all characters being ASCII constitute 'a valid UTF-8 string'.
+Returns TRUE if the first C<len> bytes of string C<s> form a valid
+Perl-extended-UTF-8 string; returns FALSE otherwise. If C<len> is 0, it will
+be calculated using C<strlen(s)> (which means if you use this option, that C<s>
+can't have embedded C<NUL> characters and has to have a terminating C<NUL>
+byte). Note that all characters being ASCII constitute 'a valid UTF-8 string'.
+
+Code points above Unicode, surrogates, and non-character code points are
+considered valid by this function.
See also L</is_utf8_invariant_string>(), L</is_utf8_string_loclen>(), and
L</is_utf8_string_loc>().
Like L</is_utf8_string> but stores the location of the failure (in the
case of "utf8ness failure") or the location C<s>+C<len> (in the case of
-"utf8ness success") in the C<ep>.
+"utf8ness success") in the C<ep> pointer.
See also L</is_utf8_string_loclen>() and L</is_utf8_string>().
Like L</is_utf8_string>() but stores the location of the failure (in the
case of "utf8ness failure") or the location C<s>+C<len> (in the case of
"utf8ness success") in the C<ep>, and the number of UTF-8
-encoded characters in the C<el>.
+encoded characters in the C<el> pointer.
See also L</is_utf8_string_loc>() and L</is_utf8_string>().