isalpha, iswalpha, _isalpha_l, _iswalpha_l

Determines whether an integer represents an alphabetic character.

Syntax

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
);

Parameters

c
Integer to test.

locale
The locale to use instead of the current locale.

Return value

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 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 isalpha and _isalpha_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.

Generic-text routine mappings

Remarks

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

Requirements

For more compatibility information, see Compatibility.

See also

Character classification
Locale
is, isw routines