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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 
);

c

Integer to test.

locale

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

_istalpha

isalpha

_ismbcalpha

iswalpha

_istalpha_l

_isalpha_l

_ismbcalpha_l

_iswalpha_l

Routine

Required header

isalpha

<ctype.h>

iswalpha

<ctype.h> or <wchar.h>

_isalpha_l

<ctype.h>

_iswalpha_l

<ctype.h> or <wchar.h>

For additional compatibility information, see Compatibility.

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