isblank, iswblank, _isblank_l, _iswblank_l

Determines whether an integer represents a blank character.

Syntax

int isblank(  
   int c   
);  
int iswblank(  
   wint_t c   
);  
int _isblank_l(  
   int c,  
   _locale_t locale  
);  
int _iswblank_l(  
   wint_t c,  
   _locale_t locale  
);  

Parameters

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 or horizontal tab character, or is one of a locale-specific set of characters that are used to separate words within a line of text. isblank returns a nonzero value if c is a space character (0x20) or horizontal tab character (0x09). The result of the test condition for the isblank functions depends on the LC_CTYPE category setting of the locale; for more information, see setlocale, _wsetlocale. The versions of these functions that do not have the _l suffix use the current locale for any locale-dependent behavior; the versions that do have the _l suffix are identical except that they use the locale that's passed in instead. For more information, see Locale.

iswblank returns a nonzero value if c is a wide character that corresponds to a standard space or horizontal tab character.

The behavior of isblank and _isblank_l is undefined if c is not EOF or in the range 0 through 0xFF, inclusive. When a debug CRT library is used and c is not one of these values, the functions raise an assertion.

Generic-Text Routine Mappings

TCHAR.H routine _UNICODE & _MBCS not defined _MBCS defined _UNICODE defined
_istblank isblank _ismbcblank iswblank
_istblank_l _isblank_l _ismbcblank_l _iswblank_l

Requirements

Routine Required header
isblank <ctype.h>
iswblank <ctype.h> or <wchar.h>
_isblank_l <ctype.h>
_iswblank_l <ctype.h> or <wchar.h>

For additional compatibility information, see Compatibility.

See Also

Character Classification
Locale
is, isw Routines