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isxdigit, iswxdigit, _isxdigit_l, _iswxdigit_l

Determines whether an integer represents a character that is a hexadecimal digit.

int isxdigit(
   int c 
int iswxdigit(
   wint_t c 
int _isxdigit_l(
   int c,
   _locale_t locale
int _iswxdigit_l(
   wint_t c,
   _locale_t locale


Integer to test.


Locale to use.

Each of these routines returns nonzero if c is a particular representation of a hexadecimal digit. isxdigit returns a nonzero value if c is a hexadecimal digit (A – F, a – f, or 0 – 9). iswxdigit returns a nonzero value if c is a wide character that corresponds to a hexadecimal digit character. Each of these routines returns 0 if c does not satisfy the test condition.

For the "C" locale, the iswxdigit function does not support Unicode full-width hexadecimal characters.

The versions of these functions that have the _l suffix use the locale that's passed in instead of the current locale for their locale-dependent behavior. For more information, see Locale.

The behavior of isxdigit and _isxdigit_l is undefined if c is not EOF or in the range 0 through 0xFF, inclusive. When a debug CRT library is used and c is not one of these values, the functions raise an assertion.

Generic-Text Routine Mappings

TCHAR.H routine

_UNICODE & _MBCS not defined

_MBCS defined

_UNICODE defined






Required header




<ctype.h> or <wchar.h>




<ctype.h> or <wchar.h>

For additional compatibility information, see Compatibility.

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