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iswalnum

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

Checks if the given wide character is an alphanumeric character, i.e. either a number (0123456789), an uppercase letter (ABCDEFGHIJKLMNOPQRSTUVWXYZ), a lowercase letter (abcdefghijklmnopqrstuvwxyz) or any alphanumeric character specific to the current locale.

Parameters

ch - wide character

Return value

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

Notes

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

Example

#include <stdio.h>
#include <wchar.h>
#include <wctype.h>
#include <locale.h>
 
int main(void)
{
    wchar_t c = L'\u13ad'; // the Cherokee letter HA ('Ꭽ')
    printf("in the default locale, iswalnum(%#x) = %d\n", c, !!iswalnum(c));
    setlocale(LC_ALL, "en_US.utf8");
    printf("in Unicode locale, iswalnum(%#x) = %d\n", c, !!iswalnum(c));
}

Output:

in the default locale, iswalnum(0x13ad) = 0
in Unicode locale, iswalnum(0x13ad) = 1

References

  • C11 standard (ISO/IEC 9899:2011):
    • 7.30.2.1.1 The iswalnum function (p: 448)
  • C99 standard (ISO/IEC 9899:1999):
    • 7.25.2.1.1 The iswalnum function (p: 394)

See also

checks if a character is alphanumeric
(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 :;<=>[email protected] 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

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