numpunct<>
specifies numeric punctuation
. The specializations required in Table
64 (
[locale.category]), namely
numpunct<wchar_t>
and
numpunct<char>,
provide classic
"C"
numeric formats,
i.e., they contain information equivalent to that contained in the
"C"
locale or their wide character counterparts as if obtained by
a call to
widen.The syntax for number formats is as follows, where
digit
represents the radix set specified by the
fmtflags
argument value, and
thousands-sep
and
decimal-point
are the results of corresponding
numpunct<charT>
members
. Integer values have the format:
integer ::= [sign] units
sign ::= plusminus
plusminus ::= '+' | '-'
units ::= digits [thousands-sep units]
digits ::= digit [digits]
and floating-point values have:
floatval ::= [sign] units [decimal-point [digits]] [e [sign] digits] |
[sign] decimal-point digits [e [sign] digits]
e ::= 'e' | 'E'
where the number of digits between
thousands-seps
is as specified by
do_grouping(). For parsing, if the
digits
portion contains no thousands-separators, no grouping constraint
is applied
.