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.
For wctype(): 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.1‐2008 defers to the ISO C standard.
The wctype() and wctype_l() functions are defined for valid character
class names as defined in the current locale or in the locale
represented by locale, respectively.
The property argument is a string identifying a generic character
class for which codeset-specific type information is required. The
following character class names shall be defined in all locales:
alnum digit punctalpha graph spaceblank lower uppercntrl print xdigit
Additional character class names defined in the locale definition
file (category LC_CTYPE) can also be specified.
These functions shall return a value of type wctype_t, which can be
used as the second argument to subsequent calls of iswctype() and
The wctype() and wctype_l() functions shall determine values of
wctype_t according to the rules of the coded character set defined by
character type information in the current locale or in the locale
represented by locale, respectively (category LC_CTYPE).
The values returned by wctype() shall be valid until a call to
setlocale() that modifies the category LC_CTYPE.
The values returned by wctype_l() shall be valid only in calls to
iswctype_l() with a locale represented by locale with the same
LC_CTYPE category value.
The behavior is undefined if the locale argument to wctype_l() is the
special locale object LC_GLOBAL_LOCALE or is not a valid locale
The wctype() and wctype_l() functions shall return 0 if the given
character class name is not valid for the current locale (category
LC_CTYPE); otherwise, they shall return an object of type wctype_t
that can be used in calls to iswctype() and iswctype_l().
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1, 2013 Edition, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The Open
Group Base Specifications Issue 7, Copyright (C) 2013 by the
Institute of Electrical and Electronics Engineers, Inc and The Open
Group. (This is POSIX.1-2008 with the 2013 Technical Corrigendum 1
applied.) 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.unix.org/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
IEEE/The Open Group 2013 WCTYPE(3P)