|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|
|
PROLOG | NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | EXAMPLES | APPLICATION USAGE | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
|
|
|
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
corresponding Linux manual page for details of Linux behavior), or
the interface may not be implemented on Linux.
iswctype, iswctype_l — test character for a specified class
#include <wctype.h>
int iswctype(wint_t wc, wctype_t charclass);
int iswctype_l(wint_t wc, wctype_t charclass,
locale_t locale);
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.
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.
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. */
yes_or_no=iswctype(wc,valid_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"))
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)
None.
None.
iswalnum(3p), iswalpha(3p), iswcntrl(3p), iswdigit(3p),
iswgraph(3p), iswlower(3p), iswprint(3p), iswpunct(3p),
iswspace(3p), iswupper(3p), iswxdigit(3p), setlocale(3p),
uselocale(3p), wctype(3p)
The Base Definitions volume of POSIX.1‐2017, locale.h(0p),
wctype.h(0p)
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(3P)
Pages that refer to this page: wchar.h(0p), wctype.h(0p), iswalnum(3p), iswalpha(3p), iswblank(3p), iswcntrl(3p), iswdigit(3p), iswgraph(3p), iswlower(3p), iswprint(3p), iswpunct(3p), iswspace(3p), iswupper(3p), iswxdigit(3p), setlocale(3p), wctype(3p)
|
HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|