std::iswcntrl
Defined in header <cwctype>
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int iswcntrl( std::wint_t ch ); |
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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 <iostream> #include <cwctype> #include <clocale> 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 locale (function template) | |
checks if a character is a control character (function) |
ASCII values | characters |
iscntrl |
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---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
decimal | hexadecimal | octal | |||||||||||||
0–8 | \x0 –\x8
|
\0 –\10
|
control codes (NUL , etc.)
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
9 | \x9
|
\11
|
tab (\t )
|
≠0
|
0
|
≠0
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
10–13 | \xA –\xD
|
\12 –\15
|
whitespaces (\n , \v , \f , \r )
|
≠0
|
0
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
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 QRSTUVWXYZ
|
0
|
≠0
|
0
|
0
|
≠0
|
0
|
≠0
|
≠0
|
≠0
|
0
|
0
|
0
|
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 qrstuvwxyz
|
0
|
≠0
|
0
|
0
|
≠0
|
0
|
≠0
|
≠0
|
0
|
≠0
|
0
|
0
|
123–126 | \x7B –\x7E
|
\172 –\176
|
{|}~
|
0
|
≠0
|
0
|
0
|
≠0
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
127 | \x7F
|
\177
|
backspace character (DEL )
|
≠0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|
0
|