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Determines whether a particular character is an ASCII character.
Syntax
int __isascii(
int c
);
int iswascii(
wint_t c
);
#define isascii __isascii
Parameters
c
Integer to test.
Return value
Each of these routines returns nonzero if c is a particular representation of an ASCII character. __isascii returns a nonzero value if c is an ASCII character (in the range 0x00 - 0x7F). iswascii returns a nonzero value if c is a wide-character representation of an ASCII character. Each of these routines returns 0 if c doesn't satisfy the test condition.
Remarks
Both __isascii and iswascii are implemented as macros unless the preprocessor macro _CTYPE_DISABLE_MACROS is defined.
For backward compatibility, isascii is implemented as a macro only if __STDC__ isn't defined or is defined as 0; otherwise it's undefined.
By default, this function's global state is scoped to the application. To change this scope, see Global state in the CRT.
Generic-text routine mappings
| Tchar.h routine | _UNICODE and _MBCS not defined |
_MBCS defined |
_UNICODE defined |
|---|---|---|---|
_istascii |
__isascii |
__isascii |
iswascii |
Requirements
| Routine | Required header |
|---|---|
isascii, __isascii |
C: <ctype.h> C++: <cctype> or <ctype.h> |
iswascii |
C: <wctype.h>, <ctype.h>, or <wchar.h> C++: <cwctype>, <cctype>, <wctype.h>, <ctype.h>, or <wchar.h> |
The isascii, __isascii, and iswascii functions are Microsoft-specific. For more compatibility information, see Compatibility.