islower, iswlower, _islower_l, _iswlower_l
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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.