WCSXFRM

Section: POSIX Programmer's Manual (3P)
Updated: 2003
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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 - wide-character string transformation

SYNOPSIS

#include <wchar.h>

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

DESCRIPTION

The wcsxfrm() function 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() applied to the same two original wide-character strings. 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() function 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(), then check errno.

RETURN VALUE

The wcsxfrm() function 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() function may set errno, but no return value is reserved to indicate an error.

ERRORS

The wcsxfrm() function 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 program's 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.

COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 .