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.
Return Value
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. For more information, see Locale.
Generic-Text Routine Mappings
TCHAR.H routine |
_UNICODE & _MBCS not defined |
_MBCS defined |
_UNICODE defined |
|---|---|---|---|
_istdigit |
isdigit |
iswdigit |
|
_istdigit_l |
_isdigit_l |
_iswdigit_l |
Requirements
Routine |
Required header |
|---|---|
isdigit |
<ctype.h> |
iswdigit |
<ctype.h> or <wchar.h> |
_isdigit_l |
<ctype.h> |
_iswdigit_l |
<ctype.h> or <wchar.h> |
For additional compatibility information, see Compatibility in the Introduction.