PROLOG

       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.

NAME

       wcsxfrm, wcsxfrm_l — wide-character string transformation

SYNOPSIS

       #include <wchar.h>

       size_t wcsxfrm(wchar_t *restrict ws1, const wchar_t *restrict ws2,
           size_t n);
       size_t wcsxfrm_l(wchar_t *restrict ws1, const wchar_t *restrict ws2,
           size_t n, locale_t locale);

DESCRIPTION

       For  wcsxfrm():  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  wcsxfrm() and wcsxfrm_l() functions shall transform the wide-character string pointed
       to by ws2 and place the resulting wide-character string into the array pointed to by  ws1.
       The  transformation  shall  be  such  that  if wcscmp() is applied to two transformed wide
       strings, it shall return a value greater than, equal to, or less than 0, corresponding  to
       the  result  of  wcscoll() and wcscoll_l() applied to the same two original wide-character
       strings, and the same LC_COLLATE category of the  current  locale  or  the  locale  object
       locale,  respectively.  No  more  than  n  wide-character  codes  shall be placed into the
       resulting array pointed to by ws1, including the terminating null wide-character code.  If
       n is 0, ws1 is permitted to be a null pointer. If copying takes place between objects that
       overlap, the behavior is undefined.

       The wcsxfrm() and  wcsxfrm_l()  functions  shall  not  change  the  setting  of  errno  if
       successful.

       Since  no  return  value is reserved to indicate an error, an application wishing to check
       for error situations should set errno to 0, then call wcsxfrm() or wcsxfrm_l(), then check
       errno.

       The  behavior  is  undefined  if  the locale argument to wcsxfrm_l() is the special locale
       object LC_GLOBAL_LOCALE or is not a valid locale object handle.

RETURN VALUE

       The wcsxfrm() and wcsxfrm_l() functions shall return the length of the  transformed  wide-
       character  string  (not  including the terminating null wide-character code). If the value
       returned is n or more, the contents of the array pointed to by ws1 are unspecified.

       On error, the wcsxfrm() and wcsxfrm_l() functions may set errno, but no  return  value  is
       reserved to indicate an error.

ERRORS

       These functions may fail if:

       EINVAL The  wide-character  string pointed to by ws2 contains wide-character codes outside
              the domain of the collating sequence.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       The transformation function is such that two transformed  wide-character  strings  can  be
       ordered by wcscmp() as appropriate to collating sequence information in the current locale
       (category LC_COLLATE).

       The fact that when n is 0 ws1 is permitted to be a null pointer is useful to determine the
       size of the ws1 array prior to making the transformation.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       wcscmp(), wcscoll()

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

COPYRIGHT

       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 .