NAME¶

std::iswcntrl - std::iswcntrl

Synopsis¶

Defined in header <cwctype>
int iswcntrl( std::wint_t ch );

Checks if the given wide character is a control character, i.e. codes 0x00-0x1F and
0x7F and any control characters specific to the current locale.

If the value of ch is neither representable as a wchar_t nor equal to the value of
the macro WEOF, the behavior is undefined.

Parameters¶

ch - wide character

Return value¶

Non-zero value if the wide character is a control character, zero otherwise.

Notes¶

ISO 30112 defines POSIX control characters as Unicode characters U+0000..U+001F,
U+007F..U+009F, U+2028, and U+2029 (Unicode classes Cc, Zl, and Zp).

Example¶

// Run this code

#include <clocale>
#include <cwctype>
#include <iostream>

int main()
{
wchar_t c = L'\u2028'; // the Unicode character "line separator"

std::cout << std::hex << std::showbase << std::boolalpha;
std::cout << "in the default locale, iswcntrl(" << (std::wint_t)c << ") = "
<< (bool)std::iswcntrl(c) << '\n';
std::setlocale(LC_ALL, "en_US.utf8");
std::cout << "in Unicode locale, iswcntrl(" << (std::wint_t)c << ") = "
<< (bool)std::iswcntrl(c) << '\n';
}

Output:¶

in the default locale, iswcntrl(0x2028) = false
in Unicode locale, iswcntrl(0x2028) = true

See also¶

checks if a character is classified as a control character by a
iscntrl(std::locale) locale
(function template)
iscntrl checks if a character is a control character
(function)
C documentation for
iswcntrl

ASCII values characters iscntrl isprint isspace isblank isgraph ispunct isalnum isalpha isupper islower isdigit isxdigit decimal hexadecimal octal iswcntrl iswprint iswspace iswblank iswgraph iswpunct iswalnum iswalpha iswupper iswlower iswdigit iswxdigit 0–8 \x0–\x8 \0–\10 control codes ≠0 0 0 0 0 0 0 0 0 0 0 0
(NUL, etc.) 9 \x9 \11 tab (\t) ≠0 0 ≠0 ≠0 0 0 0 0 0 0 0 0
whitespaces 10–13 \xA–\xD \12–\15 (\n, \v, \f, ≠0 0 ≠0 0 0 0 0 0 0 0 0 0
\r) 14–31 \xE–\x1F \16–\37 control codes ≠0 0 0 0 0 0 0 0 0 0 0 0 32 \x20 \40 space 0 ≠0 ≠0 ≠0 0 0 0 0 0 0 0 0 33–47 \x21–\x2F \41–\57 !"#$%&'()*+,-./ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0 48–57 \x30–\x39 \60–\71 0123456789 0 ≠0 0 0 ≠0 0 ≠0 0 0 0 ≠0 ≠0 58–64 \x3A–\x40 \72–\100 :;<=>?@ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0 65–70 \x41–\x46 \101–\106 ABCDEF 0 ≠0 0 0 ≠0 0 ≠0 ≠0 ≠0 0 0 ≠0 71–90 \x47–\x5A \107–\132 GHIJKLMNOP 0 ≠0 0 0 ≠0 0 ≠0 ≠0 ≠0 0 0 0
QRSTUVWXYZ 91–96 \x5B–\x60 \133–\140 [\]^_` 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0 97–102 \x61–\x66 \141–\146 abcdef 0 ≠0 0 0 ≠0 0 ≠0 ≠0 0 ≠0 0 ≠0 103–122 \x67–\x7A \147–\172 ghijklmnop 0 ≠0 0 0 ≠0 0 ≠0 ≠0 0 ≠0 0 0
qrstuvwxyz 123–126 \x7B–\x7E \172–\176 {|}~ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0 127 \x7F \177 backspace ≠0 0 0 0 0 0 0 0 0 0 0 0
character (DEL)