int iswblank(wint_t wc);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
iswblank(): _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE; or cc -std=c99
The iswblank() function is the wide-character equivalent of the
isblank(3) function. It tests whether wc is a wide character belonging
to the wide-character class "blank".
The wide-character class "blank" is a subclass of the wide-character
Being a subclass of the wide-character class "space", the wide-charac-
ter class "blank" is disjoint from the wide-character class "graph" and
therefore also disjoint from its subclasses "alnum", "alpha", "upper",
"lower", "digit", "xdigit", "punct".
The wide-character class "blank" always contains at least the space
character and the control character '\t'.
The iswblank() function returns non-zero if wc is a wide character
belonging to the wide-character class "blank". Otherwise it returns
The behavior of iswblank() depends on the LC_CTYPE category of the cur-
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GNU 2007-07-26 ISWBLANK(3)
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