iswalpha

< c‎ | string‎ | wide
 
C
 
Strings library
 
Null-terminated wide strings
Functions
Character manipulation
(C95)
iswalpha
(C95)
(C95)
(C95)
(C95)
(C95)
(C99)
(C95)
(C95)
(C95)
(C95)
(C95)
(C95)
(C95)
(C95)
(C95)
(C95)
(C95)
Conversions to numeric formats
(C95)(C99)
(C95)(C99)
(C99)(C95)(C99)
(C99)(C99)
String manipulation
(C95)(C11)
(C95)(C11)
(C95)(C11)
(C95)(C11)
(C95)(C11)
(C95)
(C95)
(C95)
(C95)
(C95)
(C95)
(C95)
(C95)
(C95)
(C95)
(C95)(C11)
Array manipulation
(C95)(C11)
(C95)(C11)
(C95)
(C95)
(C95)
 
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 ('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));
}

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)

See also

 checks if a character is alphabetic
(function)
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
0–8 \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
10–13 \xA–\xD \12–\15 whitespaces (\n, \v, \f, \r) ≠0 0 ≠0 0 0 0 0 0 0 0 0 0
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
QRSTUVWXYZ 		0 ≠0 0 0 ≠0 0 ≠0 ≠0 ≠0 0 0 0
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
qrstuvwxyz 		0 ≠0 0 0 ≠0 0 ≠0 ≠0 0 ≠0 0 0
123–126 \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