iswalpha
Header: <wctype.h>
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( wint_t ch );
(since C95)
# Parameters
ch: wide character
# Return value
Non-zero value if the wide character is an alphabetic character, zero otherwise.
# Notes
ISO 30112 specifies which Unicode characters are include in POSIX alpha category.
# Example
#include <locale.h>
#include <stdio.h>
#include <wchar.h>
#include <wctype.h>
int main(void)
{
wchar_t c = L'\u0b83'; // Tamil sign Visarga ('ஃ')
printf("in the default locale, iswalpha(%#x) = %d\n", c, !!iswalpha(c));
setlocale(LC_ALL, "en_US.utf8");
printf("in Unicode locale, iswalpha(%#x) = %d\n", c, !!iswalpha(c));
}