int isalnum( int c );
int iswalnum( wint_t c );
Each of these routines returns true if c is a particular representation of an alphanumeric character.
| Routine | Required Header | Compatibility |
| isalnum | <ctype.h> | ANSI, Win 95, Win NT |
| iswalnum | <ctype.h> or <wchar.h> | ANSI, Win 95, Win NT |
For additional compatibility information, see Compatibility in the Introduction.
Libraries
| LIBC.LIB | Single thread static library, retail version |
| LIBCMT.LIB | Multithread static library, retail version |
| MSVCRT.LIB | Import library for MSVCRT.DLL, retail version |
Return Value
isalnum returns a non-zero value if either isalpha or isdigit is true for c, that is, if c is within the ranges A – Z, a – z, or 0 – 9. iswalnum returns a non-zero value if either iswalpha or iswdigit is true for c. Each of these routines returns 0 if c does not satisfy the test condition.
The result of the test condition for the isalnum function depends on the LC_CTYPE category setting of the current locale; see setlocale for more information. For iswalnum, the result of the test condition is independent of locale.
Parameter
c
Integer to test
Generic-Text Routine Mappings
| TCHAR.H Routine | _UNICODE & _MBCS Not Defined | _MBCS Defined | _UNICODE Defined |
| _istalnum | isalnum | _ismbcalnum | iswalnum |
Character Classification Routines | Locale Routines | is, isw Function Overview