These wide-character classification routines return non-zero if
wc belongs to the tested wide-character class in the program's
current locale, or return zero for false.
The character to be tested, wc, must be of type
wint_t. Its value must be
the value of a valid wide-character code in the current locale;
otherwise, its value must equal
the value of WEOF. The behavior of these routines
is unpredictable if wc has any other values
or is of the wrong type.
With the exception of
iswctype(S),
these routines only take one argument, wc.
For
iswctype( ),
the result is also unpredictable
if the value of its other argument, charclass, is not valid.
This could be caused by a charclass, for example,
not obtained by a call to
wctype(S)
or caused by a call to
setlocale(S)
that has changed category LC_CTYPE.
iswalnum
tests if any character wc is a wide-character code
belonging to class alpha
or digit.
iswalpha
tests if any character wc is a wide-character code
belonging to class alpha, an alphabetic wide-character code.
iswcntrl
tests if any character wc is a wide-character code
belonging to class control, a control wide-character code.
iswdigit
tests if any character wc is a wide-character code
belonging to class digit, a decimal digit wide-character code.
iswgraph
tests if any character wc is a wide-character code
belonging to class graph,
a wide-character code with a visible representation.
iswlower
tests if any character wc is a wide-character code
belonging to class lower, a lower-case letter wide-character code.
iswprint
tests if any character wc is a wide-character code
belonging to class print, a printing wide-character code.
iswpunct
tests if any character wc is a wide-character code
belonging to class punct, a punctuation wide-character code.
iswspace
tests if any character wc is a wide-character code
belonging to class space, a white-space wide-character code.
iswupper
tests if any character wc is a wide-character code
belonging to class upper, an upper-case letter wide-character code.
iswxdigit
tests if any character wc is a wide-character code
belonging to class xdigit, a hexadecimal digit wide-character code.
iswctype
tests if any wide-character code wc
belongs to the specified character class, charclass.
There are twelve reserved strings for the standard character
classes:
alnum
alpha
blank
cntrl
digit
graph
lower
print
punct
space
upper
xdigit
Except for "blank", i.e.,
iswctype(wc, wctype("blank")),
the use of one of these strings in
iswctype( )
is equivalent to a call to one of the above eleven
isw*( )
routines.
For example, the calls
iswctype(wc, wctype("alnum"))
and iswalnum(wc) are equivalent.
For maximum portability, especially for internationalized
applications, use only these routines to classify
wide-character codes.
Return values
These wide-character classification routines return non-zero if
wc belongs to the tested wide-character class in the program's
current locale, or return zero for false.