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.\" 3. 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.\" FreeBSD: src/lib/libc/string/strxfrm.3,v 1.16 2002/09/06 11:24:06 tjr Exp 32.\" 33.Dd October 4, 2002 34.Dt WCSXFRM 3 35.Os 36.Sh NAME 37.Nm wcsxfrm 38.Nd transform a wide string under locale 39.Sh LIBRARY 40.Lb libc 41.Sh SYNOPSIS 42.In wchar.h 43.Ft size_t 44.Fn wcsxfrm "wchar_t * restrict dst" "const wchar_t * restrict src" "size_t n" 45.Sh DESCRIPTION 46The 47.Fn wcsxfrm 48function transforms a null-terminated wide character string pointed to by 49.Fa src 50according to the current locale collation order 51then copies the transformed string 52into 53.Fa dst . 54No more than 55.Fa n 56wide characters are copied into 57.Fa dst , 58including the terminating null character added. 59If 60.Fa n 61is set to 0 62(it helps to determine an actual size needed 63for transformation), 64.Fa dst 65is permitted to be a 66.Dv NULL 67pointer. 68.Pp 69Comparing two strings using 70.Fn wcscmp 71after 72.Fn wcsxfrm 73is equivalent to comparing 74two original strings with 75.Fn wcscoll . 76.Sh RETURN VALUES 77Upon successful completion, 78.Fn wcsxfrm 79returns the length of the transformed string not including 80the terminating null character. 81If this value is 82.Fa n 83or more, the contents of 84.Fa dst 85are indeterminate. 86.Sh SEE ALSO 87.Xr setlocale 3 , 88.Xr strxfrm 3 , 89.Xr wcscmp 3 , 90.Xr wcscoll 3 91.Sh STANDARDS 92The 93.Fn wcsxfrm 94function 95conforms to 96.St -isoC-99 . 97.Sh BUGS 98The current implementation of 99.Fn wcsxfrm 100only works in single-byte 101.Dv LC_CTYPE 102locales, and falls back to using 103.Fn wcsncpy 104in locales with extended character sets. 105.Pp 106Comparing two strings using 107.Fn wcscmp 108after 109.Fn wcsxfrm 110is 111.Em not 112always equivalent to comparison with 113.Fn wcscoll ; 114.Fn wcsxfrm 115only stores information about primary collation weights into 116.Fa dst , 117whereas 118.Fn wcscoll 119compares characters using both primary and secondary weights. 120