std::iswalpha
Min standard notice:
Header: <cwctype>
Checks if the given wide character is an alphabetic character, i.e. either an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), a lowercase letter (abcdefghijklmnopqrstuvwxyz) or any alphabetic character specific to the current locale.
# Declarations
int iswalpha( std::wint_t ch );
# Parameters
ch: wide character
# Return value
Non-zero value if the wide character is an alphabetic character, 0 otherwise.
# Notes
ISO 30112 specifies which Unicode characters are include in POSIX alpha category.
# Example
#include <clocale>
#include <cwctype>
#include <iostream>
int main()
{
wchar_t c = L'\u0b83'; // Tamil sign Visarga ('ஃ')
std::cout << std::hex << std::showbase << std::boolalpha;
std::cout << "in the default locale, iswalpha(" << (std::wint_t)c << ") = "
<< (bool)std::iswalpha(c) << '\n';
std::setlocale(LC_ALL, "en_US.utf8");
std::cout << "in Unicode locale, iswalpha(" << (std::wint_t)c << ") = "
<< (bool)std::iswalpha(c) << '\n';
}