[apple/libc.git] / string / wcsxfrm.3

.\" Copyright (c) 1990, 1991, 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" Chris Torek and the American National Standards Committee X3,
.\" on Information Processing Systems.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\"     @(#)strxfrm.3	8.1 (Berkeley) 6/4/93
.\" FreeBSD: src/lib/libc/string/strxfrm.3,v 1.16 2002/09/06 11:24:06 tjr Exp
.\" $FreeBSD: src/lib/libc/string/wcsxfrm.3,v 1.2 2002/12/09 14:04:05 ru Exp $
.\"
.Dd October 4, 2002
.Dt WCSXFRM 3
.Os
.Sh NAME
.Nm wcsxfrm ,
.Nm wcsxfrm_l
.Nd transform a wide string under locale
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In wchar.h
.Ft size_t
.Fo wcsxfrm
.Fa "wchar_t *restrict ws1"
.Fa "const wchar_t *restrict ws2"
.Fa "size_t n"
.Fc
.In wchar.h
.In xlocale.h
.Ft size_t
.Fo wcsxfrm_l
.Fa "wchar_t *restrict ws1"
.Fa "const wchar_t *restrict ws2"
.Fa "size_t n"
.Fa "locale_t loc"
.Fc
.Sh DESCRIPTION
The
.Fn wcsxfrm
function transforms a null-terminated wide character string pointed to by
.Fa ws2 ,
according to the current locale's collation order,
then copies the transformed string into
.Fa ws1 .
No more than
.Fa n
wide characters are copied into
.Fa ws1 ,
including the terminating null character.
If
.Fa n
is set to 0
(it helps to determine an actual size needed
for transformation),
.Fa ws1
is permitted to be a
.Dv NULL
pointer.
.Pp
Comparing two strings using
.Fn wcscmp
after
.Fn wcsxfrm
is equivalent to comparing
two original strings with
.Fn wcscoll .
.Pp
Although the
.Fn wcsxfrm
function uses the current locale, the
.Fn wcsxfrm_l
function may be passed a locale directly. See
.Xr xlocale 3
for more information.
.Sh RETURN VALUES
Upon successful completion,
.Fn wcsxfrm
returns the length of the transformed string not including
the terminating null character.
If this value is
.Fa n
or more, the contents of
.Fa ws1
are indeterminate.
.Sh SEE ALSO
.Xr setlocale 3 ,
.Xr strxfrm 3 ,
.Xr wcscmp 3 ,
.Xr wcscoll 3 ,
.Xr xlocale 3
.Sh STANDARDS
The
.Fn wcsxfrm
function
conforms to
.St -isoC-99 .
.Sh BUGS
The current implementation of
.Fn wcsxfrm
only works in single-byte
.Dv LC_CTYPE
locales, and falls back to using
.Fn wcsncpy
in locales with extended character sets.
.Pp
Comparing two strings using
.Fn wcscmp
after
.Fn wcsxfrm
is
.Em not
always equivalent to comparison with
.Fn wcscoll ;
.Fn wcsxfrm
only stores information about primary collation weights into
.Fa ws1 ,
whereas
.Fn wcscoll
compares characters using both primary and secondary weights.
Commit	Line	Data
224c7076 A	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. All advertising materials mentioning features or use of this software
	17	.\" must display the following acknowledgement:
	18	.\" This product includes software developed by the University of
	19	.\" California, Berkeley and its contributors.
	20	.\" 4. Neither the name of the University nor the names of its contributors
	21	.\" may be used to endorse or promote products derived from this software
	22	.\" without specific prior written permission.
	23	.\"
	24	.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	25	.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	26	.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	27	.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	28	.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	29	.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	30	.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	31	.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	32	.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	33	.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	34	.\" SUCH DAMAGE.
	35	.\"
	36	.\" @(#)strxfrm.3 8.1 (Berkeley) 6/4/93
	37	.\" FreeBSD: src/lib/libc/string/strxfrm.3,v 1.16 2002/09/06 11:24:06 tjr Exp
	38	.\" $FreeBSD: src/lib/libc/string/wcsxfrm.3,v 1.2 2002/12/09 14:04:05 ru Exp $
	39	.\"
	40	.Dd October 4, 2002
	41	.Dt WCSXFRM 3
	42	.Os
	43	.Sh NAME
	44	.Nm wcsxfrm ,
	45	.Nm wcsxfrm_l
	46	.Nd transform a wide string under locale
	47	.Sh LIBRARY
	48	.Lb libc
	49	.Sh SYNOPSIS
	50	.In wchar.h
	51	.Ft size_t
	52	.Fo wcsxfrm
	53	.Fa "wchar_t *restrict ws1"
	54	.Fa "const wchar_t *restrict ws2"
	55	.Fa "size_t n"
	56	.Fc
	57	.In wchar.h
	58	.In xlocale.h
	59	.Ft size_t
	60	.Fo wcsxfrm_l
	61	.Fa "wchar_t *restrict ws1"
	62	.Fa "const wchar_t *restrict ws2"
	63	.Fa "size_t n"
	64	.Fa "locale_t loc"
65	.Fc
66	.Sh DESCRIPTION
67	The
68	.Fn wcsxfrm
69	function transforms a null-terminated wide character string pointed to by
70	.Fa ws2 ,
71	according to the current locale's collation order,
72	then copies the transformed string into
73	.Fa ws1 .
74	No more than
75	.Fa n
76	wide characters are copied into
77	.Fa ws1 ,
78	including the terminating null character.
79	If
80	.Fa n
81	is set to 0
82	(it helps to determine an actual size needed
83	for transformation),
84	.Fa ws1
85	is permitted to be a
86	.Dv NULL
87	pointer.
88	.Pp
89	Comparing two strings using
90	.Fn wcscmp
91	after
92	.Fn wcsxfrm
93	is equivalent to comparing
94	two original strings with
95	.Fn wcscoll .
96	.Pp
97	Although the
98	.Fn wcsxfrm
99	function uses the current locale, the
100	.Fn wcsxfrm_l
101	function may be passed a locale directly. See
102	.Xr xlocale 3
103	for more information.
104	.Sh RETURN VALUES
105	Upon successful completion,
106	.Fn wcsxfrm
107	returns the length of the transformed string not including
108	the terminating null character.
109	If this value is
110	.Fa n
111	or more, the contents of
112	.Fa ws1
113	are indeterminate.
114	.Sh SEE ALSO
115	.Xr setlocale 3 ,
116	.Xr strxfrm 3 ,
117	.Xr wcscmp 3 ,
118	.Xr wcscoll 3 ,
119	.Xr xlocale 3
120	.Sh STANDARDS
121	The
122	.Fn wcsxfrm
123	function
124	conforms to
125	.St -isoC-99 .
126	.Sh BUGS
127	The current implementation of
128	.Fn wcsxfrm
129	only works in single-byte
130	.Dv LC_CTYPE
131	locales, and falls back to using
132	.Fn wcsncpy
133	in locales with extended character sets.
134	.Pp
135	Comparing two strings using
136	.Fn wcscmp
137	after
138	.Fn wcsxfrm
139	is
140	.Em not
141	always equivalent to comparison with
142	.Fn wcscoll ;
143	.Fn wcsxfrm
144	only stores information about primary collation weights into
145	.Fa ws1 ,
146	whereas
147	.Fn wcscoll
148	compares characters using both primary and secondary weights.