140 lines
3.2 KiB
Groff
140 lines
3.2 KiB
Groff
.\" Copyright (c) 2002-2004 Tim J. Robbins
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.\" All rights reserved.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd April 8, 2004
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.Dt MBRTOWC 3
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.Os
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.Sh NAME
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.Nm mbrtowc
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.Nd "convert a character to a wide-character code (restartable)"
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In wchar.h
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.Ft size_t
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.Fo mbrtowc
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.Fa "wchar_t * restrict pwc" "const char * restrict s" "size_t n"
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.Fa "mbstate_t * restrict ps"
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.Fc
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.Sh DESCRIPTION
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The
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.Fn mbrtowc
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function inspects at most
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.Fa n
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bytes pointed to by
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.Fa s
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to determine the number of bytes needed to complete the next multibyte
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character.
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If a character can be completed, and
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.Fa pwc
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is not
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.Dv NULL ,
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the wide character which is represented by
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.Fa s
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is stored in the
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.Vt wchar_t
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it points to.
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.Pp
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If
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.Fa s
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is
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.Dv NULL ,
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.Fn mbrtowc
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behaves as if
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.Fa pwc
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was
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.Dv NULL ,
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.Fa s
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was an empty string
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.Pq Qq
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and
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.Fa n
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was 1.
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.Pp
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The
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.Vt mbstate_t
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argument,
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.Fa ps ,
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is used to keep track of the shift state.
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If it is
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.Dv NULL ,
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.Fn mbrtowc
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uses an internal, static
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.Vt mbstate_t
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object, which is initialized to the initial conversion state
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at program startup.
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.Sh RETURN VALUES
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The
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.Fn mbrtowc
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functions returns:
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.Bl -tag -width indent
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.It 0
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The next
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.Fa n
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or fewer bytes
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represent the null wide character
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.Pq Li "L'\e0'" .
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.It >0
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The next
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.Fa n
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or fewer bytes
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represent a valid character,
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.Fn mbrtowc
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returns the number of bytes used to complete the multibyte character.
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.It Po Vt size_t Pc Ns \-2
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The next
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.Fa n
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contribute to, but do not complete, a valid multibyte character sequence,
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and all
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.Fa n
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bytes have been processed.
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.It Po Vt size_t Pc Ns \-1
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An encoding error has occurred.
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The next
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.Fa n
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or fewer bytes do not contribute to a valid multibyte character.
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.El
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.Sh ERRORS
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The
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.Fn mbrtowc
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function will fail if:
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.Bl -tag -width Er
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.It Bq Er EILSEQ
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An invalid multibyte sequence was detected.
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.It Bq Er EINVAL
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The conversion state is invalid.
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.El
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.Sh SEE ALSO
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.Xr mbtowc 3 ,
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.Xr multibyte 3 ,
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.Xr setlocale 3 ,
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.Xr wcrtomb 3
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.Sh STANDARDS
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The
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.Fn mbrtowc
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function conforms to
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.St -isoC-99 .
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