islower, iswlower, _islower_l, _iswlower_l

Determines whether an integer represents a lowercase character.

Syntax

int islower(  
   int c   
);  
int iswlower(  
   wint_t c   
);  
int islower_l(  
   int c,  
   _locale_t locale  
);  
int _iswlower_l(  
   wint_t c,  
   _locale_t locale  
);  

Parameters

c
Integer to test.

locale
Locale to use.

Return Value

Each of these routines returns nonzero if c is a particular representation of a lowercase character. islower returns a nonzero value if c is a lowercase character (a - z). iswlower returns a nonzero value if c is a wide character that corresponds to a lowercase letter, or if c is one of an implementation-defined set of wide characters 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 that's passed in instead of the current locale for their locale-dependent behavior. For more information, see Locale.

The behavior of islower and _islower_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
_istlower islower _ismbclower iswlower
_istlower_l _islower _l _ismbclower_l _liswlower_l

Requirements

Routine Required header
islower <ctype.h>
iswlower <ctype.h> or <wchar.h>
_islower_l <ctype.h>
_swlower_l <ctype.h> or <wchar.h>

For additional compatibility information, see Compatibility.

See Also

Character Classification
Locale
is, isw Routines