std::iswctype (3) Linux Manual Page

std::iswctype – std::iswctype

Synopsis

Defined in header<cwctype>

    int iswctype(std::wint_t wc, std::wctype_t desc);

Classifies the wide character wc using the current C locale’s LC_CTYPE category identified by desc.
If the value of wc is neither representable as a wchar_t nor equal to the value of the macro WEOF, the behavior is undefined.

Parameters

wc – the wide character to classify
desc – the LC_CTYPE category, obtained from a call to std::wctype

Return value

Non-zero if the character ch has the property identified by desc in LC_CTYPE facet of the current C locale, zero otherwise.

Example

// Run this code

#include <clocale>

#include <cwctype>

#include <iostream>

bool classify(wchar_t wc, const std::string &cat)

{
    return std::iswctype(wc, std::wctype(cat.c_str()));
}

int main()

{
    std::setlocale(LC_ALL, "ja_JP.UTF-8");
    std::cout << "The character \u6c34 is...\n";
    for (std::string s : {"digit", "alpha", "space", "cntrl", "jkanji"})
        std::cout << s << "? " << std::boolalpha << classify(L'\u6c34', s) << '\n';
}

Output:

  The character 水 is…
  digit? false
  alpha? true
  space? false
  cntrl? false
  jkanji? true

See also

       looks up a character classification category in the current C locale
wctype (function)