ISWCTYPE(3P)                                        POSIX Programmer's Manual                                       ISWCTYPE(3P)



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

NAME
       iswctype - test character for a specified class

SYNOPSIS
       #include <wctype.h>

       int iswctype(wint_t wc, wctype_t charclass);


DESCRIPTION
       The  iswctype()  function shall determine whether the wide-character code wc has the character class charclass, returning
       true or false. The iswctype() function is defined on WEOF and wide-character codes corresponding to the  valid  character
       encodings in the current locale. 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.

RETURN VALUE
       The iswctype() function shall return non-zero (true) if and only if wc has the property described by charclass.  If char-
       class is 0, iswctype() shall return 0.

ERRORS
       No errors are defined.

       The following sections are informative.

EXAMPLES
   Testing for a Valid Character
              #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);

APPLICATION USAGE
       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 equiv-
       alent to the functions in the right column.


              iswalnum(wc)    iswctype(wc, wctype("alnum"))
              iswalpha(wc)    iswctype(wc, wctype("alpha"))
              iswblank(wc)    iswctype(wc, wctype("blank"))
              iswcntrl(wc)    iswctype(wc, wctype("cntrl"))
              iswdigit(wc)    iswctype(wc, wctype("digit"))
              iswgraph(wc)    iswctype(wc, wctype("graph"))
              iswlower(wc)    iswctype(wc, wctype("lower"))
              iswprint(wc)    iswctype(wc, wctype("print"))
              iswpunct(wc)    iswctype(wc, wctype("punct"))
              iswspace(wc)    iswctype(wc, wctype("space"))
              iswupper(wc)    iswctype(wc, wctype("upper"))
              iswxdigit(wc)   iswctype(wc, wctype("xdigit"))

RATIONALE
       None.

FUTURE DIRECTIONS
       None.

SEE ALSO
       iswalnum(), iswalpha(), iswcntrl(), iswdigit(), iswgraph(), iswlower(), iswprint(), iswpunct(),  iswspace(),  iswupper(),
       iswxdigit(), setlocale(), wctype(), the Base Definitions volume of IEEE Std 1003.1-2001, <wchar.h>, <wctype.h>

COPYRIGHT
       Portions  of  this  text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for
       Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6,  Copy-
       right (C) 2001-2003 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.open-
       group.org/unix/online.html .



IEEE/The Open Group                                           2003                                                  ISWCTYPE(3P)