NAME¶

std::iswalpha - std::iswalpha

Synopsis¶

Defined in header <cwctype>
int iswalpha( std::wint_t ch );

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.

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¶

// Run this code

#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';
}

Possible output:¶

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

See also¶

isalpha(std::locale) checks if a character is classified as alphabetic by a locale
(function template)
isalpha checks if a character is alphabetic
(function)
C documentation for
iswalpha

ASCII values characters iscntrl isprint isspace isblank isgraph ispunct isalnum isalpha isupper islower isdigit isxdigit decimal hexadecimal octal iswcntrl iswprint iswspace iswblank iswgraph iswpunct iswalnum iswalpha iswupper iswlower iswdigit iswxdigit 0–8 \x0–\x8 \0–\10 control codes ≠0 0 0 0 0 0 0 0 0 0 0 0
(NUL, etc.) 9 \x9 \11 tab (\t) ≠0 0 ≠0 ≠0 0 0 0 0 0 0 0 0
whitespaces 10–13 \xA–\xD \12–\15 (\n, \v, \f, ≠0 0 ≠0 0 0 0 0 0 0 0 0 0
\r) 14–31 \xE–\x1F \16–\37 control codes ≠0 0 0 0 0 0 0 0 0 0 0 0 32 \x20 \40 space 0 ≠0 ≠0 ≠0 0 0 0 0 0 0 0 0 33–47 \x21–\x2F \41–\57 !"#$%&'()*+,-./ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0 48–57 \x30–\x39 \60–\71 0123456789 0 ≠0 0 0 ≠0 0 ≠0 0 0 0 ≠0 ≠0 58–64 \x3A–\x40 \72–\100 :;<=>?@ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0 65–70 \x41–\x46 \101–\106 ABCDEF 0 ≠0 0 0 ≠0 0 ≠0 ≠0 ≠0 0 0 ≠0 71–90 \x47–\x5A \107–\132 GHIJKLMNOP 0 ≠0 0 0 ≠0 0 ≠0 ≠0 ≠0 0 0 0
QRSTUVWXYZ 91–96 \x5B–\x60 \133–\140 [\]^_` 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0 97–102 \x61–\x66 \141–\146 abcdef 0 ≠0 0 0 ≠0 0 ≠0 ≠0 0 ≠0 0 ≠0 103–122 \x67–\x7A \147–\172 ghijklmnop 0 ≠0 0 0 ≠0 0 ≠0 ≠0 0 ≠0 0 0
qrstuvwxyz 123–126 \x7B–\x7E \172–\176 {|}~ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0 127 \x7F \177 backspace ≠0 0 0 0 0 0 0 0 0 0 0 0
character (DEL)