Proposed resolution:
This wording is relative to N4727.
Edit [charconv.from.chars] as indicated:
from_chars_result from_chars(const char* first, const char* last, float& value, chars_format fmt = chars_format::general); from_chars_result from_chars(const char* first, const char* last, double& value, chars_format fmt = chars_format::general); from_chars_result from_chars(const char* first, const char* last, long double& value, chars_format fmt = chars_format::general);-6- Requires: fmt has the value of one of the enumerators of chars_format.
-7- Effects: The pattern is the expected form of the subject sequence in the "C" locale, as described for strtod, except that
(7.1) — the
onlysign '+'thatmay only appearis '-'in the exponent part;(7.2) […]
(7.3) […]
(7.4) […]