iswctype(1) test character for a specified class


#include <wctype.h>

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 unspecified.


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


No errors are defined.

The following sections are informative.


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. */


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"))
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"))






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, 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 .