std::iswblank

int iswblank( std::wint_t ch );

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

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

#include <iostream>
#include <cwctype>
#include <clocale>
 
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';
}

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

See also