std::iswxdigit
Min standard notice:
Header: <cwctype>
Checks if the given wide character corresponds (if narrowed) to a hexadecimal numeric character, i.e. one of 0123456789abcdefABCDEF.
# Declarations
int iswxdigit( wint_t ch );
# Parameters
ch: wide character
# Return value
Non-zero value if the wide character is a hexadecimal numeric character, zero otherwise.
# Notes
std::iswdigit and std::iswxdigit are the only standard wide character classification functions that are not affected by the currently installed C locale.
# Example
#include <cwctype>
#include <iostream>
int main()
{
std::cout << std::boolalpha
<< (std::iswxdigit(L'a') != 0) << ' '
<< (std::iswxdigit(L'ä') != 0) << '\n';
}