NAME¶

std::iswblank - std::iswblank

Synopsis¶

Defined in header <cwctype>
int iswblank( std::wint_t ch ); (since C++11)

Checks if the given wide character is classified as blank character (that is, a
whitespace character used to separate words in a sentence) by the current C locale.
In the default C locale, only space (0x20) and horizontal tab (0x09) are blank
characters.

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 blank character, zero otherwise.

Notes¶

ISO 30112 defines POSIX blank characters as Unicode characters U+0009, U+0020,
U+1680, U+180E, U+2000..U+2006, U+2008, U+200A, U+205F, and U+3000.

Example¶

// Run this code

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

int main()
{
wchar_t c = L'\u3000'; // Ideographic space ('　')

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

Output:¶

in the default locale, iswblank(0x3000) = false
in Unicode locale, iswblank(0x3000) = true

See also¶

isblank(std::locale) checks if a character is classified as a blank character by a
(C++11) locale
(function template)
isblank checks if a character is a blank character
(C++11) (function)
C documentation for
iswblank

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)