string/FreeBSD/wcsxfrm.3

   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 .Nm wcsxfrm_l
  42 .Nd transform a wide string under locale
  43 .Sh LIBRARY
  44 .Lb libc
  45 .Sh SYNOPSIS
  46 .In wchar.h
  47 .Ft size_t
  48 .Fo wcsxfrm
  49 .Fa "wchar_t *restrict ws1"
  50 .Fa "const wchar_t *restrict ws2"
  51 .Fa "size_t n"
  52 .Fc
  53 .In wchar.h
  54 .In xlocale.h
  55 .Ft size_t
  56 .Fo wcsxfrm_l
  57 .Fa "wchar_t *restrict ws1"
  58 .Fa "const wchar_t *restrict ws2"
  59 .Fa "size_t n"
  60 .Fa "locale_t loc"
  61 .Fc
  62 .Sh DESCRIPTION
  63 The
  64 .Fn wcsxfrm
  65 function transforms a null-terminated wide character string pointed to by
  66 .Fa ws2 ,
  67 according to the current locale's collation order,
  68 then copies the transformed string into
  69 .Fa ws1 .
  70 No more than
  71 .Fa n
  72 wide characters are copied into
  73 .Fa ws1 ,
  74 including the terminating null character.
  75 If
  76 .Fa n
  77 is set to 0
  78 (it helps to determine an actual size needed
  79 for transformation),
  80 .Fa ws1
  81 is permitted to be a
  82 .Dv NULL
  83 pointer.
  84 .Pp
  85 Comparing two strings using
  86 .Fn wcscmp
  87 after
  88 .Fn wcsxfrm
  89 is equivalent to comparing
  90 two original strings with
  91 .Fn wcscoll .
  92 .Pp
  93 Although the
  94 .Fn wcsxfrm
  95 function uses the current locale, the
  96 .Fn wcsxfrm_l
  97 function may be passed a locale directly. See
  98 .Xr xlocale 3
  99 for more information.
 100 .Sh RETURN VALUES
 101 Upon successful completion,
 102 .Fn wcsxfrm
 103 returns the length of the transformed string not including
 104 the terminating null character.
 105 If this value is
 106 .Fa n
 107 or more, the contents of
 108 .Fa ws1
 109 are indeterminate.
 110 .Sh SEE ALSO
 111 .Xr setlocale 3 ,
 112 .Xr strxfrm 3 ,
 113 .Xr wcscmp 3 ,
 114 .Xr wcscoll 3 ,
 115 .Xr xlocale 3
 116 .Sh STANDARDS
 117 The
 118 .Fn wcsxfrm
 119 function
 120 conforms to
 121 .St -isoC-99 .
 122 .Sh BUGS
 123 The current implementation of
 124 .Fn wcsxfrm
 125 only works in single-byte
 126 .Dv LC_CTYPE
 127 locales, and falls back to using
 128 .Fn wcsncpy
 129 in locales with extended character sets.
 130 .Pp
 131 Comparing two strings using
 132 .Fn wcscmp
 133 after
 134 .Fn wcsxfrm
 135 is
 136 .Em not
 137 always equivalent to comparison with
 138 .Fn wcscoll ;
 139 .Fn wcsxfrm
 140 only stores information about primary collation weights into
 141 .Fa ws1 ,
 142 whereas
 143 .Fn wcscoll
 144 compares characters using both primary and secondary weights.