WCSXFRM(3)                 POSIX Programmer's Manual                WCSXFRM(3)



PROLOG
       This manual page is part of the POSIX Programmer's Manual.  The OS
       implementation of this interface may differ (consult the corresponding
       OS manual page for details of OS behavior), or the interface may not be
       implemented on OS.

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 .



IEEE/The Open Group                  2017                           WCSXFRM(3)
