std::iswalpha

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.

If the value of ch is neither representable as a wchar_t nor equal to the value of the macro WEOF, the behavior is undefined.

[edit] Parameters

[edit] Return value

Non-zero value if the wide character is an alphabetic character, ​0​ otherwise.

[edit] Notes

ISO 30112 specifies which Unicode characters are include in POSIX alpha category.

[edit] 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';
}

in the default locale, iswalpha(0xb83) = false
in Unicode locale, iswalpha(0xb83) = true

[edit] See also