isdigit, iswdigit, _isdigit_l, _iswdigit_l
Determines if a particular character is a decimal-digit character.
int isdigit( int c ); int iswdigit( wint_t c ); int _isdigit_l( int c, _locale_t locale ); int _iswdigit_l( wint_t c, _locale_t locale );
Parameters
- c
-
Integer to test.
- locale
-
The locale to use.
Each of these routines returns nonzero if c is a particular representation of a decimal-digit character. isdigit returns a nonzero value if c is a decimal digit (0 – 9). iswdigit returns a nonzero value if c is a wide character corresponding to a decimal-digit character. Each of these routines returns 0 if c does not satisfy the test condition.
When used with a debug CRT library, isdigit 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, isdigit 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 |
|---|---|---|---|
| _istdigit | isdigit | iswdigit | |
| _istdigit_l | _isdigit_l | _iswdigit_l |
| Routine | Required header | Compatibility |
|---|---|---|
| isdigit | <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 |
| iswdigit | <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 |
| _isdigit_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 |
| _iswdigit_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.
