iswblank

< c‎ | string‎ | wide
Defined in header <wctype.h>
int iswblank( wint_t ch );
 (since C99)

Checks if the given wide character is classified as blank character (that is, a whitespace character used to separate words in a sentence) by the current C locale. In the default C locale, only space (0x20) and horizontal tab (0x09) are blank characters.

Parameters

ch - wide character

Return value

Non-zero value if the wide character is a blank character, zero otherwise.

Notes

ISO 30112 defines POSIX blank characters as Unicode characters U+0009, U+0020, U+1680, U+180E, U+2000..U+2006, U+2008, U+200A, U+205F, and U+3000.

Example

#include <stdio.h>
#include <wchar.h>
#include <wctype.h>
#include <locale.h>
 
int main(void)
{
    wchar_t c = L'\u3000'; // Ideographic space ('　')
    printf("in the default locale, iswblank(%#x) = %d\n", c, !!iswblank(c));
    setlocale(LC_ALL, "en_US.utf8");
    printf("in Unicode locale, iswblank(%#x) = %d\n", c, !!iswblank(c));
}

Output:

in the default locale, iswblank(0x3000) = 0
in Unicode locale, iswblank(0x3000) = 1

References

  • C11 standard (ISO/IEC 9899:2011):
  • 7.30.2.1.3 The iswblank function (p: 449)
  • C99 standard (ISO/IEC 9899:1999):
  • 7.25.2.1.3 The iswblank function (p: 395)

See also

(C99)
 checks if a character is a blank character
(function)
ASCII values characters

iscntrl
iswcntrl

isprint
iswprint

isspace
iswspace

isblank
iswblank

isgraph
iswgraph

ispunct
iswpunct

isalnum
iswalnum

isalpha
iswalpha

isupper
iswupper

islower
iswlower

isdigit
iswdigit

isxdigit
iswxdigit
decimal hexadecimal octal
0–8 \x0–\x8 \0–\10 control codes (NUL, etc.) ≠0 0 0 0 0 0 0 0 0 0 0 0
9 \x9 \11 tab (\t) ≠0 0 ≠0 ≠0 0 0 0 0 0 0 0 0
10–13 \xA–\xD \12–\15 whitespaces (\n, \v, \f, \r) ≠0 0 ≠0 0 0 0 0 0 0 0 0 0
14–31 \xE–\x1F \16–\37 control codes ≠0 0 0 0 0 0 0 0 0 0 0 0
32 \x20 \40 space 0 ≠0 ≠0 ≠0 0 0 0 0 0 0 0 0
33–47 \x21–\x2F \41–\57 !"#$%&'()*+,-./ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0
48–57 \x30–\x39 \60–\71 0123456789 0 ≠0 0 0 ≠0 0 ≠0 0 0 0 ≠0 ≠0
58–64 \x3A–\x40 \72–\100 :;<=>?@ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0
65–70 \x41–\x46 \101–\106 ABCDEF 0 ≠0 0 0 ≠0 0 ≠0 ≠0 ≠0 0 0 ≠0
71–90 \x47–\x5A \107–\132 GHIJKLMNOP
QRSTUVWXYZ		 0 ≠0 0 0 ≠0 0 ≠0 ≠0 ≠0 0 0 0
91–96 \x5B–\x60 \133–\140 [\]^_` 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0
97–102 \x61–\x66 \141–\146 abcdef 0 ≠0 0 0 ≠0 0 ≠0 ≠0 0 ≠0 0 ≠0
103–122 \x67–\x7A \147–\172 ghijklmnop
qrstuvwxyz		 0 ≠0 0 0 ≠0 0 ≠0 ≠0 0 ≠0 0 0
123–126 \x7B–\x7E \172–\176 {|}~ 0 ≠0 0 0 ≠0 ≠0 0 0 0 0 0 0
127 \x7F \177 backspace character (DEL) ≠0 0 0 0 0 0 0 0 0 0 0 0