isalnum, iswalnum, _isalnum_l, _iswalnum_l
Determines whether an integer represents an alphanumeric character.
int isalnum( int c ); int iswalnum( wint_t c ); int _isalnum_l( int c, _locale_t locale ); int _iswalnum_l( wint_t c, _locale_t locale );
Each of these routines returns nonzero if c is a particular representation of an alphanumeric character. isalnum returns a nonzero value if either isalpha or isdigit is nonzero for c, that is, if c is within the ranges A – Z, a – z, or 0 – 9. iswalnum returns a nonzero value if either iswalpha or iswdigit is nonzero for c. Each of these routines returns 0 if c does not satisfy the test condition.
The versions of these functions that have the _l suffix use the locale parameter that's passed in instead of the current locale. For more information, see Locale.
The behavior of isalnum and _isalnum_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.
|
TCHAR.H routine |
_UNICODE & _MBCS not defined |
_MBCS defined |
_UNICODE defined |
|---|---|---|---|
|
_istalnum |
isalnum |
iswalnum |
|
|
_istalnum_l |
_isalnum_l |
_ismbcalnum_l |
_iswalnum_l |
|
Routine |
Required header |
|---|---|
|
isalnum |
<ctype.h> |
|
iswalnum |
<ctype.h> or <wchar.h> |
|
_isalnum_l |
<ctype.h> |
|
_iswalnum_l |
<ctype.h> or <wchar.h> |
For additional compatibility information, see Compatibility.
