Section: POSIX Programmer's Manual (3P)
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
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or the interface may not be implemented on Linux.
--- wide-character string transformation
size_t wcsxfrm(wchar_t *restrict ws1, const wchar_t *restrict ws2,
size_t wcsxfrm_l(wchar_t *restrict ws1, const wchar_t *restrict ws2,
size_t n, locale_t locale);
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.
functions shall transform the wide-character string pointed to by
and place the resulting wide-character string into the array pointed to
The transformation shall be such that if
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
applied to the same two original wide-character strings, and the same
category of the current locale
or the locale object
respectively. No more than
wide-character codes shall be placed into the resulting array pointed
including the terminating null wide-character code. If
is permitted to be a null pointer. If copying takes place between
objects that overlap, the behavior is undefined.
functions shall not change the setting of
Since no return value is reserved to indicate an error, an
application wishing to check for error situations should set
to 0, then call
The behavior is undefined if the
is the special locale object LC_GLOBAL_LOCALE or is not a valid locale
functions shall return the length of the transformed wide-character
string (not including the terminating null wide-character code). If the
value returned is
or more, the contents of the array pointed to by
On error, the
functions may set
but no return value is reserved to indicate an error.
These functions may fail if:
The wide-character string pointed to by
contains wide-character codes outside the domain of the collating
The following sections are informative.
The transformation function is such that two transformed wide-character
strings can be ordered by
as appropriate to collating sequence information in the current locale
The fact that when
is permitted to be a null pointer is useful to determine the size of
array prior to making the transformation.
The Base Definitions volume of POSIX.1-2008,
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
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