### 4.18 `iswcntrl`, `iswcntrl_l`—control wide character test ¶

Synopsis

    #include <wctype.h>
    int iswcntrl(wint_t c);

    #include <wctype.h>
    int iswcntrl_l(wint_t c, locale_t locale);

Description
`iswcntrl` is a function which classifies wide-character values that are categorized as control characters.

`iswcntrl_l` is like `iswcntrl` but performs the check based on the locale specified by the locale object locale. If locale is LC_GLOBAL_LOCALE or not a valid locale object, the behaviour is undefined.

Returns
`iswcntrl`, `iswcntrl_l` return non-zero if c is a control wide character.

Portability
`iswcntrl` is C99. `iswcntrl_l` is POSIX-1.2008.

No supporting OS subroutines are required.