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.\" 32.\" @(#)strxfrm.3 8.1 (Berkeley) 6/4/93 33.\" $FreeBSD: head/lib/libc/string/wcsxfrm.3 251069 2013-05-28 20:57:40Z emaste $ 34.\" 35.Dd December 25, 2013 36.Dt WCSXFRM 3 37.Os 38.Sh NAME 39.Nm wcsxfrm , 40.Nm wcsxfrm_l 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.Ft size_t 49.Fn wcsxfrm_l "wchar_t * restrict dst" "const wchar_t * restrict src" "size_t n" "locale_t locale" 50.Sh DESCRIPTION 51The 52.Fn wcsxfrm 53function transforms a null-terminated wide character string pointed to by 54.Fa src 55according to the current locale collation order 56then copies the transformed string 57into 58.Fa dst . 59No more than 60.Fa n 61wide characters are copied into 62.Fa dst , 63including the terminating null character added. 64If 65.Fa n 66is set to 0 67(it helps to determine an actual size needed 68for transformation), 69.Fa dst 70is permitted to be a 71.Dv NULL 72pointer. 73.Pp 74Comparing two strings using 75.Fn wcscmp 76after 77.Fn wcsxfrm 78is equivalent to comparing 79two original strings with 80.Fn wcscoll . 81.Pp 82The 83.Fn wcsxfrm_l 84function is identical to 85.Fn wcsxfrm 86but takes an explicit 87.Fa locale 88argument, whereas 89.Fn wcsxfrm 90uses the current global or per-thread locale. 91.Sh RETURN VALUES 92Upon successful completion, 93.Fn wcsxfrm 94and 95.Fn wcsxfrm_l 96return the length of the transformed string not including 97the terminating null character. 98If this value is 99.Fa n 100or more, the contents of 101.Fa dst 102are indeterminate. 103.Sh SEE ALSO 104.Xr setlocale 3 , 105.Xr strxfrm 3 , 106.Xr wcscmp 3 , 107.Xr wcscoll 3 108.Sh STANDARDS 109The 110.Fn wcsxfrm 111function 112conforms to 113.St -isoC-99 . 114The 115.Fn wcsxfrm_l 116function conforms to 117.St -p1003.1-2008 . 118.Sh BUGS 119The current implementation of 120.Fn wcsxfrm 121and 122.Fn wcsxfrm_l 123only works in single-byte 124.Dv LC_CTYPE 125locales, and falls back to using 126.Fn wcsncpy 127in locales with extended character sets. 128.Pp 129Comparing two strings using 130.Fn wcscmp 131after 132.Fn wcsxfrm 133is 134.Em not 135always equivalent to comparison with 136.Fn wcscoll ; 137.Fn wcsxfrm 138only stores information about primary collation weights into 139.Fa dst , 140whereas 141.Fn wcscoll 142compares characters using both primary and secondary weights. 143