std::iswblank
Min standard notice:
Header: <cwctype>
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.
# Declarations
int iswblank( std::wint_t ch );
(since C++11)
# 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
#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';
}