iswalpha

Defined in header `<wctype.h>`
int iswalpha( wint_t ch );		(since C95)

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.

Parameters

ch

-

wide character

Return value

Non-zero value if the wide character is a alphabetic character, zero otherwise.

Notes

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

Example

Run this code

#include <stdio.h>
#include <wchar.h>
#include <wctype.h>
#include <locale.h>

int main(void)
{
    wchar_t c = L'\u0b83'; // Tamil sign Visarga ('')
    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));
}

Output:

in the default locale, iswalpha(0xb83) = 0
in Unicode locale, iswalpha(0xb83) = 1

References

C11 standard (ISO/IEC 9899:2011):

7.30.2.1.2 The iswalpha function (p: 448-449)

C99 standard (ISO/IEC 9899:1999):

7.25.2.1.2 The iswalpha function (p: 394-395)

ASCII values			characters	`iscntrl` `iswcntrl`	`isprint` `iswprint`	`isspace` `iswspace`	`isblank` `iswblank`	`isgraph` `iswgraph`	`ispunct` `iswpunct`	`isalnum` `iswalnum`	`isalpha` `iswalpha`	`isupper` `iswupper`	`islower` `iswlower`	`isdigit` `iswdigit`	`isxdigit` `iswxdigit`
decimal	hexadecimal	octal	characters	`iscntrl` `iswcntrl`	`isprint` `iswprint`	`isspace` `iswspace`	`isblank` `iswblank`	`isgraph` `iswgraph`	`ispunct` `iswpunct`	`isalnum` `iswalnum`	`isalpha` `iswalpha`	`isupper` `iswupper`	`islower` `iswlower`	`isdigit` `iswdigit`	`isxdigit` `iswxdigit`
08	`\x0\x8`	`\0\10`	control codes (`NUL`, etc.)	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
9	`\x9`	`\11`	tab (`\t`)	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
1013	`\xA\xD`	`\12\15`	whitespaces (`\n`, `\v`, `\f`, `\r`)	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
1431	`\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`
3347	`\x21\x2F`	`\41\57`	`!"#$%&'()*+,-./`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
4857	`\x30\x39`	`\60\71`	`0123456789`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
5864	`\x3A\x40`	`\72\100`	`:;<=>?@`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
6570	`\x41\x46`	`\101\106`	`ABCDEF`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
7190	`\x47\x5A`	`\107\132`	`GHIJKLMNOP` `QRSTUVWXYZ`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
9196	`\x5B\x60`	`\133\140`	[\]^_`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
97102	`\x61\x66`	`\141\146`	`abcdef`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
103122	`\x67\x7A`	`\147\172`	`ghijklmnop` `qrstuvwxyz`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
123126	`\x7B\x7E`	`\172\176`	`{\|}~`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`
127	`\x7F`	`\177`	backspace character (`DEL`)	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`	`0`

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