1.\" Copyright (c) 1990, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" This code is derived from software contributed to Berkeley by 5.\" Chris Torek and the American National Standards Committee X3, 6.\" on Information Processing Systems. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 1. Redistributions of source code must retain the above copyright 12.\" notice, this list of conditions and the following disclaimer. 13.\" 2. Redistributions in binary form must reproduce the above copyright 14.\" notice, this list of conditions and the following disclaimer in the 15.\" documentation and/or other materials provided with the distribution. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)strxfrm.3 8.1 (Berkeley) 6/4/93 33.\" FreeBSD: src/lib/libc/string/strxfrm.3,v 1.16 2002/09/06 11:24:06 tjr Exp 34.\" $FreeBSD: src/lib/libc/string/wcsxfrm.3,v 1.3 2007/01/09 00:28:12 imp Exp $ 35.\" 36.Dd October 4, 2002 37.Dt WCSXFRM 3 38.Os 39.Sh NAME 40.Nm wcsxfrm 41.Nd transform a wide string under locale 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In wchar.h 46.Ft size_t 47.Fn wcsxfrm "wchar_t * restrict dst" "const wchar_t * restrict src" "size_t n" 48.Sh DESCRIPTION 49The 50.Fn wcsxfrm 51function transforms a null-terminated wide character string pointed to by 52.Fa src 53according to the current locale collation order 54then copies the transformed string 55into 56.Fa dst . 57No more than 58.Fa n 59wide characters are copied into 60.Fa dst , 61including the terminating null character added. 62If 63.Fa n 64is set to 0 65(it helps to determine an actual size needed 66for transformation), 67.Fa dst 68is permitted to be a 69.Dv NULL 70pointer. 71.Pp 72Comparing two strings using 73.Fn wcscmp 74after 75.Fn wcsxfrm 76is equivalent to comparing 77two original strings with 78.Fn wcscoll . 79.Sh RETURN VALUES 80Upon successful completion, 81.Fn wcsxfrm 82returns the length of the transformed string not including 83the terminating null character. 84If this value is 85.Fa n 86or more, the contents of 87.Fa dst 88are indeterminate. 89.Sh SEE ALSO 90.Xr setlocale 3 , 91.Xr strxfrm 3 , 92.Xr wcscmp 3 , 93.Xr wcscoll 3 94.Sh STANDARDS 95The 96.Fn wcsxfrm 97function 98conforms to 99.St -isoC-99 . 100.Sh BUGS 101The current implementation of 102.Fn wcsxfrm 103only works in single-byte 104.Dv LC_CTYPE 105locales, and falls back to using 106.Fn wcsncpy 107in locales with extended character sets. 108.Pp 109Comparing two strings using 110.Fn wcscmp 111after 112.Fn wcsxfrm 113is 114.Em not 115always equivalent to comparison with 116.Fn wcscoll ; 117.Fn wcsxfrm 118only stores information about primary collation weights into 119.Fa dst , 120whereas 121.Fn wcscoll 122compares characters using both primary and secondary weights. 123