iswblank - test for whitespace wide character
int iswblank(wint_t wc);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
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-
character 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 ' '.
The iswblank() function returns nonzero if wc is a wide character
belonging to the wide-character class "blank". Otherwise it returns
Multithreading (see pthreads(7))
The iswblank() function is thread-safe with exceptions. It can be
safely used in multithreaded applications, as long as setlocale(3) is
not called to change the locale during its execution.
The behavior of iswblank() depends on the LC_CTYPE category of the
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