isalpha, iswalpha, _isalpha_l, _iswalpha_l
Determines whether an integer represents an alphabetic character.
int isalpha( int c ); int iswalpha( wint_t c ); int _isalpha_l( int c, _locale_t locale ); int _iswalpha_l( wint_t c, _locale_t locale );
Integer to test.
The locale to use instead of the current locale.
Each of these routines returns nonzero if c is a particular representation of an alphabetic character. isalpha returns a nonzero value if c is within the ranges A - Z or a - z. iswalpha returns a nonzero value only for wide characters for which iswupper or iswlower is nonzero; that is, for any wide character that is one of an implementation-defined set for which none of iswcntrl, iswdigit, iswpunct, or iswspace is nonzero. 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 isalpha and _isalpha_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|
By default, this function's global state is scoped to the application. To change this, see Global state in the CRT.
|iswalpha||<ctype.h> or <wchar.h>|
|_iswalpha_l||<ctype.h> or <wchar.h>|
For additional compatibility information, see Compatibility.