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 wctrans(): 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 wctrans() and wctrans_l() functions are defined for valid
character mapping names identified in the current locale. The
charclass is a string identifying a generic character mapping name
for which codeset-specific information is required. The following
character mapping names are defined in all locales: tolower and
These functions shall return a value of type wctrans_t, which can be
used as the second argument to subsequent calls of towctrans() and
The wctrans() and wctrans_l() functions shall determine values of
wctrans_t according to the rules of the coded character set defined
by character mapping information in the current locale or in the
locale represented by locale, respectively (category LC_CTYPE).
The values returned by wctrans() shall be valid until a call to
setlocale() that modifies the category LC_CTYPE.
The values returned by wctrans_l() shall be valid only in calls to
towctrans_l() with a locale represented by locale with the same
LC_CTYPE category value.
The behavior is undefined if the locale argument to wctrans_l() is
the special locale object LC_GLOBAL_LOCALE or is not a valid locale
The wctrans() and wctrans_l() functions shall return 0 and may set
errno to indicate the error if the given character mapping name is
not valid for the current locale (category LC_CTYPE); otherwise, they
shall return a non-zero object of type wctrans_t that can be used in
calls to towctrans() and towctrans_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 WCTRANS(3P)