ISWCTYPE(3P) POSIX Programmer's Manual ISWCTYPE(3P)
This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the correspond-
ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
iswctype - test character for a specified class
int iswctype(wint_t wc, wctype_t charclass);
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
The iswctype() function shall return non-zero (true) if and only if wc has the property described by charclass. If charclass is 0, iswc-
type() shall return 0.
No errors are defined.
The following sections are informative.
Testing for a Valid Character
if ((valid_class=wctype("vowel")) == (wctype_t)0)
/* Invalid character class. */
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
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"))
iswalnum(), iswalpha(), iswcntrl(), iswdigit(), iswgraph(), iswlower(), iswprint(), iswpunct(), iswspace(), iswupper(), iswxdigit(), setlo-
cale(), wctype(), the Base Definitions volume of IEEE Std 1003.1-2001, <wchar.h>, <wctype.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
ogy -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (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.opengroup.org/unix/online.html .
/The Open Group 2003 ISWCTYPE(3P)