b6cbf7203b
This patch imports the unmodified current version of NetBSD libc. The NetBSD includes are in /nbsd_include, while the libc code itself is split between lib/nbsd_libc and common/lib/libc.
197 lines
5.4 KiB
Groff
197 lines
5.4 KiB
Groff
.\" $NetBSD: mbrtowc.3,v 1.8 2006/10/16 09:10:29 wiz Exp $
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.\"
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.\" Copyright (c)2002 Citrus Project,
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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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.Dd February 4, 2002
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.Dt MBRTOWC 3
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.Os
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.\" ----------------------------------------------------------------------
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.Sh NAME
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.Nm mbrtowc
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.Nd converts a multibyte character to a wide character (restartable)
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.\" ----------------------------------------------------------------------
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.Sh LIBRARY
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.Lb libc
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.\" ----------------------------------------------------------------------
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.Sh SYNOPSIS
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.In wchar.h
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.Ft size_t
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.Fn mbrtowc "wchar_t * restrict pwc" "const char * restrict s" "size_t n" \
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"mbstate_t * restrict ps"
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.\" ----------------------------------------------------------------------
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.Sh DESCRIPTION
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The
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.Fn mbrtowc
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usually converts the multibyte character pointed to by
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.Fa s
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to a wide character, and stores the wide character
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to the wchar_t object pointed to by
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.Fa pwc
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if
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.Fa pwc
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is
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.Pf non- Dv NULL
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and
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.Fa s
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points to a valid character.
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The conversion happens in accordance with, and changes the conversion
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state described in the mbstate_t object pointed to by
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.Fa ps .
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This function may examine at most
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.Fa n
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bytes of the array beginning from
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.Fa s .
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.Pp
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If
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.Fa s
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points to a valid character and the character corresponds to a nul wide
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character, then the
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.Fn mbrtowc
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places the mbstate_t object pointed to by
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.Fa ps
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to an initial conversion state.
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.Pp
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Unlike
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.Xr mbtowc 3 ,
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the
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.Fn mbrtowc
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may accept the byte sequence pointed to by
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.Fa s
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not forming a complete multibyte character
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but which may be part of a valid character.
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In this case, this function will accept all such bytes
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and save them into the conversion state object pointed to by
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.Fa ps .
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They will be used at subsequent calls of this function to restart
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the conversion suspended.
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.Pp
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The behaviour of
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.Fn mbrtowc
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is affected by the
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.Dv LC_CTYPE
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category of the current locale.
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.Pp
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These are the special cases:
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.Bl -tag -width 012345678901
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.It "s == NULL"
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.Fn mbrtowc
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sets the conversion state object pointed to by
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.Fa ps
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to an initial state and always returns 0.
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Unlike
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.Xr mbtowc 3 ,
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the value returned does not indicate whether the current encoding of
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the locale is state-dependent.
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.Pp
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In this case,
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.Fn mbrtowc
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ignores
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.Fa pwc
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and
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.Fa n ,
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and is equivalent to the following call:
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.Bd -literal -offset indent
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mbrtowc(NULL, "", 1, ps);
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.Ed
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.It "pwc == NULL"
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The conversion from a multibyte character to a wide character has
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taken place and the conversion state may be affected, but the resulting
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wide character is discarded.
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.It "ps == NULL"
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.Fn mbrtowc
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uses its own internal state object to keep the conversion state,
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instead of
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.Fa ps
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mentioned in this manual page.
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.Pp
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Calling any other functions in
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.Lb libc
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never changes the internal state of
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.Fn mbrtowc ,
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which is initialized at startup time of the program.
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.El
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.\" ----------------------------------------------------------------------
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.Sh RETURN VALUES
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In the usual cases,
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.Fn mbrtowc
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returns:
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.Bl -tag -width 012345678901
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.It 0
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The next bytes pointed to by
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.Fa s
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form a nul character.
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.It positive
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If
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.Fa s
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points to a valid character,
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.Fn mbrtowc
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returns the number of bytes in the character.
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.It (size_t)-2
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.Fa s
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points to a byte sequence which possibly contains part of a valid
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multibyte character, but which is incomplete.
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When
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.Fa n
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is at least
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.Dv MB_CUR_MAX ,
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this case can only occur if the array pointed to by
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.Fa s
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contains a redundant shift sequence.
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.It (size_t)-1
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.Fa s
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points to an illegal byte sequence which does not form a valid multibyte
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character.
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In this case,
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.Fn mbrtowc
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sets
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.Va errno
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to indicate the error.
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.El
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.\" ----------------------------------------------------------------------
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.Sh ERRORS
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.Fn mbrtowc
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may cause an error in the following case:
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.Bl -tag -width Er
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.It Bq Er EILSEQ
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.Fa s
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points to an invalid or incomplete multibyte character.
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.It Bq Er EINVAL
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.Fa ps
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points to an invalid or uninitialized mbstate_t object.
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.El
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.\" ----------------------------------------------------------------------
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.Sh SEE ALSO
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.Xr mbrlen 3 ,
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.Xr mbtowc 3 ,
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.Xr setlocale 3
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.\" ----------------------------------------------------------------------
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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-amd1 .
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The restrict qualifier is added at
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.St -isoC-99 .
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