This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       The twelve strings "alnum", "alpha", "blank",  "cntrl",  "digit",  "graph",  "lower",  "print",  "punct",
       "space",  "upper",  and "xdigit" are reserved for the standard character classes. In the table below, the
       functions in the left column are equivalent to the functions in the right column.

           iswalnum(wc)            iswctype(wc, wctype("alnum"))
           iswalnum_l(wc, locale)  iswctype_l(wc, wctype("alnum"), locale)
           iswalpha(wc)            iswctype(wc, wctype("alpha"))
           iswalpha_l(wc, locale)  iswctype_l(wc, wctype("alpha"), locale)
           iswblank(wc)            iswctype(wc, wctype("blank"))
           iswblank_l(wc, locale)  iswctype_l(wc, wctype("blank"), locale)
           iswcntrl(wc)            iswctype(wc, wctype("cntrl"))
           iswcntrl_l(wc, locale)  iswctype_l(wc, wctype("cntrl"), locale)
           iswdigit(wc)            iswctype(wc, wctype("digit"))
           iswdigit_l(wc, locale)  iswctype_l(wc, wctype("digit"), locale)
           iswgraph(wc)            iswctype(wc, wctype("graph"))
           iswgraph_l(wc, locale)  iswctype_l(wc, wctype("graph"), locale)
           iswlower(wc)            iswctype(wc, wctype("lower"))
           iswlower_l(wc, locale)  iswctype_l(wc, wctype("lower"), locale)
           iswprint(wc)            iswctype(wc, wctype("print"))
           iswprint_l(wc, locale)  iswctype_l(wc, wctype("print"), locale)
           iswpunct(wc)            iswctype(wc, wctype("punct"))
           iswpunct_l(wc, locale)  iswctype_l(wc, wctype("punct"), locale)
           iswspace(wc)            iswctype(wc, wctype("space"))
           iswspace_l(wc, locale)  iswctype_l(wc, wctype("space"), locale)
           iswupper(wc)            iswctype(wc, wctype("upper"))
           iswupper_l(wc, locale)  iswctype_l(wc, wctype("upper"), locale)
           iswxdigit(wc)           iswctype(wc, wctype("xdigit"))
           iswxdigit_l(wc, locale) iswctype_l(wc, wctype("xdigit"), locale)

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard
       for  Information  Technology  --  Portable  Operating  System  Interface  (POSIX),  The  Open  Group Base
       Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical  and  Electronics
       Engineers, Inc and The Open Group.  In the event of any discrepancy between this version and the original
       IEEE  and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document.
       The original Standard can be obtained online at http://www.opengroup.org/unix/online.html .

       Any typographical or formatting errors that appear in this page are most likely to have  been  introduced
       during   the   conversion  of  the  source  files  to  man  page  format.  To  report  such  errors,  see
       https://www.kernel.org/doc/man-pages/reporting_bugs.html .

IEEE/The Open Group                                   2017                                      ISWCTYPE(3POSIX)

       For  iswctype():  The  functionality described on this reference page is aligned with the ISO C standard.
       Any conflict between the requirements described here and the ISO C standard is unintentional. This volume
       of POSIX.1‐2017 defers to the ISO C standard.

       The iswctype() and iswctype_l() functions shall determine whether the  wide-character  code  wc  has  the
       character class charclass, returning true or false. The iswctype() and iswctype_l() functions are defined
       on WEOF and wide-character codes corresponding to the valid character encodings in the current locale, or
       in  the  locale  represented  by  locale,  respectively.  If  the wc argument is not in the domain of the
       function, the result is undefined.  If the value of charclass is invalid (that is, not obtained by a call
       to wctype() or charclass is invalidated by a subsequent call to setlocale() that  has  affected  category
       LC_CTYPE) the result is unspecified.

       The  behavior  is  undefined  if  the  locale  argument  to  iswctype_l()  is  the  special locale object
       LC_GLOBAL_LOCALE or is not a valid locale object handle.

       No errors are defined.

       Thefollowingsectionsareinformative.

TestingforaValidCharacter
           #include <wctype.h>
           ...
           int yes_or_no;
           wint_t wc;
           wctype_t valid_class;
           ...
           if ((valid_class=wctype("vowel")) == (wctype_t)0)
               /* Invalid character class. */
           yes_or_no=iswctype(wc,valid_class);

       None.

       iswctype, iswctype_l — test character for a specified class

       This  manual  page  is part of the POSIX Programmer's Manual.  The Linux implementation of this interface
       may differ (consult the corresponding Linux manual page for details of Linux behavior), or the  interface
       may not be implemented on Linux.

       None.

       The iswctype() and iswctype_l() functions shall return non-zero (true) if and only if wc has the property
       described by charclass.  If charclass is (wctype_t)0, these functions shall return 0.

iswalnum(),  iswalpha(),  iswcntrl(),  iswdigit(),  iswgraph(),   iswlower(),   iswprint(),   iswpunct(),
       iswspace(), iswupper(), iswxdigit(), setlocale(), uselocale(), wctype()

       The Base Definitions volume of POSIX.1‐2017, <locale.h>, <wctype.h>

       #include <wctype.h>

       int iswctype(wint_t wc, wctype_t charclass);
       int iswctype_l(wint_t wc, wctype_t charclass,
           locale_t locale);