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C

Compiler support

Language

Headers

Type support

Program utilities

Variadic function support

Error handling

Dynamic memory management

Strings library

Algorithms

Numerics

Date and time utilities

Input/output support

Localization support

Concurrency support (C11)

Technical Specifications

Symbol index

 

Strings library

Null-terminated byte strings

Null-terminated multibyte strings

Null-terminated wide strings

 

Null-terminated wide strings

Functions Character classification iswalnum (C95) iswalpha (C95) iswlower (C95) iswupper (C95) iswdigit (C95) iswxdigit (C95)   iswblank (C99) iswctype (C95) iswcntrl (C95) iswgraph (C95) iswspace (C95) iswprint (C95) iswpunct (C95) wctype (C95) Character manipulation towlower (C95) towupper (C95) wctrans (C95) towctrans (C95) Conversions to numeric formats wcstolwcstoll (C95)(C99) wcstofwcstodwcstold (C99)(C95)(C99) wcstoulwcstoull (C95)(C99) wcstoimaxwcstoumax (C99)(C99)     String manipulation wcscpywcscpy_s (C95)(C11) wcsncpywcsncpy_s (C95)(C11) wcsxfrm (C95) wcscatwcscat_s (C95)(C11) wcsncatwcsncat_s (C95)(C11)

String examination wcslenwcsnlen_s (C95)(C11) wcsstr (C95) wcscmp (C95) wcsncmp (C95) wcscoll (C95) wcschr (C95) wcsrchr (C95) wcspbrk (C95) wcsspn (C95) wcscspn (C95) wcstokwcstok_s (C95)(C11) Array manipulation wmemcpywmemcpy_s (C95)(C11) wmemmovewmemmove_s (C95)(C11)   wmemcmp (C95) wmemchr (C95) wmemset (C95) Types wchar_t wint_t (C95) wctrans_t wctype_t (C95)(C95) Macros WCHAR_MIN WCHAR_MAX (C95)(C95) WEOF (C95)

 

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

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Checks if the given wide character corresponds (if narrowed) to a hexadecimal numeric character, i.e. one of 0123456789abcdefABCDEF.

Parameters

ch

-

wide character

Return value

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

Notes

iswdigit and iswxdigit are the only standard wide character classification functions that are not affected by the currently installed C locale.

Example

Some locales offer additional character classes that detect non-ASCII digits

Run this code

#include <locale.h>
#include <stdio.h>
#include <wchar.h>
#include <wctype.h>
 
void test(wchar_t a3, wchar_t u3, wchar_t j3)
{
    printf("\t  '%lc'  '%lc' '%lc'\n", a3, u3, j3);
    printf("iswxdigit: %d    %d    %d\n",
           !!iswxdigit(a3),
           !!iswxdigit(u3),
           !!iswxdigit(j3));
    printf("jdigit:    %d    %d    %d\n",
           !!iswctype(a3, wctype("jdigit")),
           !!iswctype(u3, wctype("jdigit")),
           !!iswctype(j3, wctype("jdigit")));
}
 
int main(void)
{
    wchar_t a3 = L'9';  // the ASCII digit 9
    wchar_t u3 = L'〩'; // the CJK numeral 9
    wchar_t j3 = L'９'; // the full-width digit 9
 
    setlocale(LC_ALL, "en_US.utf8");
    puts("In American locale:");
    test(a3, u3, j3);
 
    setlocale(LC_ALL, "ja_JP.utf8");
    puts("\nIn Japanese locale:");
    test(a3, u3, j3);
}

Possible output:

In American locale:
	  '9'  '〩' '９'
iswxdigit: 1    0    0
jdigit:    0    0    0
 
In Japanese locale:
	  '9'  '〩' '９'
iswxdigit: 1    0    0
jdigit:    0    0    1

References

• C23 standard (ISO/IEC 9899:2024):

• 7.30.2.1.12 The iswxdigit function (p: TBD)

• C17 standard (ISO/IEC 9899:2018):

• 7.30.2.1.12 The iswxdigit function (p: TBD)

• C11 standard (ISO/IEC 9899:2011):

• 7.30.2.1.12 The iswxdigit function (p: 451)

• C99 standard (ISO/IEC 9899:1999):

• 7.25.2.1.12 The iswxdigit function (p: 397)

See also

isxdigit	checks if a character is a hexadecimal character (function)
C++ documentation for iswxdigit

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	\173–\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