This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface

       None.

       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                                       WCTRANS(3POSIX)

       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.1‐2017 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 toupper.

       These functions shall return a value of type wctrans_t, which can be  used  as  the  second  argument  to
       subsequent calls of towctrans() and towctrans_l().

       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 object handle.

       These functions may fail if:

       EINVAL The character mapping name pointed to by charclass is not valid in the current locale.

       Thefollowingsectionsareinformative.

       None.

       None.

       wctrans, wctrans_l — define character mapping

       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.

       None.

       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().

towctrans()

       The Base Definitions volume of POSIX.1‐2017, <wctype.h>

       #include <wctype.h>

       wctrans_t wctrans(const char *charclass);
       wctrans_t wctrans_l(const char *charclass, locale_t locale);