iswblank

int iswblank( wint_t ch );

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

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 <locale.h>
#include <stdio.h>
#include <wchar.h>
#include <wctype.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));
}

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

References

• C23 standard (ISO/IEC 9899:2023):
• 7.30.2.1.3 The iswblank function (p: TBD)
• C17 standard (ISO/IEC 9899:2018):
• 7.30.2.1.3 The iswblank function (p: TBD)
• 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