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 );

c
Integer to test.

locale
The locale to use.

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 doesn't 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 isn't EOF or in the range 0 through 0xFF, inclusive. When a debug CRT library is used and c isn't one of these values, the functions raise an assertion.

By default, this function's global state is scoped to the application. To change this behavior, see Global state in the CRT.

For more compatibility information, see Compatibility.

Character classification
Locale
is, isw routines