isspace, iswspace, _isspace_l, _iswspace_l

 Determines if a particular character represents a space character.

int isspace(
   int c 
int iswspace(
   wint_t c 
int _isspace_l(
   int c,
   _locale_t locale
int _iswspace_l(
   wint_t c,
   _locale_t locale


  • c
    Integer to test.

  • locale
    Locale to use.

Return Value

Each of these routines returns nonzero if c is a particular representation of a space character. isspace returns a nonzero value if c is a white-space character (0x09 – 0x0D or 0x20). The result of the test condition for the isspacefunction depends on the LC_CTYPE category setting of the locale; see setlocale for more information. The versions of these functions without the _lsuffix use the current locale for any locale-dependent behavior; the versions with the _l suffix are identical except that they use the locale passed in instead. For more information, see Locale.

iswspace returns a nonzero value if c is a wide character that corresponds to a standard white-space character.

When used with a debug CRT library, isspace 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 non-debug CRT library, isspace 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.

Generic-Text Routine Mappings

TCHAR.H routine

_UNICODE & _MBCS not defined

_MBCS defined

_UNICODE defined







Required header




<ctype.h> or <wchar.h>




<ctype.h> or <wchar.h>

For additional compatibility information, see Compatibility in the Introduction.

.NET Framework Equivalent


See Also


Character Classification


is, isw Routines