islower, iswlower, _islower_l, _iswlower_l
Determines if a particular character is in lower case.
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.
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.
When used with a debug CRT library, islower will display a CRT assert if passed a parameter that is not EOF or in the range of 0 through 0xFF. When used with a debug CRT library, islower will use the parameter as an index into an array, with undefined results if the parameter is not EOF or in the range of 0 through 0xFF.
The versions of these functions with the _l suffix are identical except that they use the locale passed in instead of the current locale for their locale-dependent behavior.
| TCHAR.H routine | _UNICODE & _MBCS not defined | _MBCS defined | _UNICODE defined |
|---|---|---|---|
| _istlower | islower | iswlower | |
| _istlower_l | _islower _l | _liswlower_l |
| Routine | Required header | Compatibility |
|---|---|---|
| islower | <ctype.h> | ANSI, Windows 95, Windows 98, Windows 98 Second Edition, Windows Millennium Edition, Windows NT 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 |
| iswlower | <ctype.h> or <wchar.h> | ANSI, Windows 95, Windows 98, Windows 98 Second Edition, Windows Millennium Edition, Windows NT 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 |
| _islower_l | <ctype.h> | Windows 95, Windows 98, Windows 98 Second Edition, Windows Millennium Edition, Windows NT 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 |
| _swlower_l | <ctype.h> or <wchar.h> | Windows 95, Windows 98, Windows 98 Second Edition, Windows Millennium Edition, Windows NT 4.0, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 |
For additional compatibility information, see Compatibility in the Introduction.
