isblank, iswblank, _isblank_l, _iswblank_l
The new home for Visual Studio documentation is Visual Studio 2017 Documentation on docs.microsoft.com.
The latest version of this topic can be found at 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.