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isblank, iswblank, _isblank_l, _iswblank_l

Determines whether an integer represents a blank character.

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
);

c

Integer to test.

locale

Locale to use.

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

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.

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