freebsd-nq/lib/libc/locale/mbtowc.3

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.\" Copyright (c) 2002-2004 Tim J. Robbins. All rights reserved.
.\" Copyright (c) 1993
.\" The Regents of the University of California. All rights reserved.
.\"
.\" This code is derived from software contributed to Berkeley by
.\" Donn Seeley of BSDI.
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.\" modification, are permitted provided that the following conditions
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.\" notice, this list of conditions and the following disclaimer.
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.\" 3. All advertising materials mentioning features or use of this software
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.\" 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.
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.\" From @(#)multibyte.3 8.1 (Berkeley) 6/4/93
.\" From FreeBSD: src/lib/libc/locale/multibyte.3,v 1.22 2003/11/08 03:23:11 tjr Exp
.\" $FreeBSD$
.\"
.Dd April 11, 2004
.Dt MBTOWC 3
.Os
.Sh NAME
.Nm mbtowc
.Nd convert a character to a wide-character code
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In stdlib.h
.Ft int
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.Fo mbtowc
.Fa "wchar_t * restrict wcharp" "const char * restrict mbchar"
.Fa "size_t nbytes"
.Fc
.Sh DESCRIPTION
The
.Fn mbtowc
function converts a multibyte character
.Fa mbchar
into a wide character according to the current conversion state,
and stores the result
in the object pointed to by
.Fa wcharp .
Up to
.Fa nbytes
bytes are examined.
.Pp
A call with a null
.Fa mbchar
pointer returns nonzero if the current encoding requires shift states,
zero otherwise;
if shift states are required, the shift state is reset to the initial state.
.Sh RETURN VALUES
If
.Fa mbchar
is
.Dv NULL ,
the
.Fn mbtowc
function returns nonzero if shift states are supported,
zero otherwise.
.Pp
Otherwise, if
.Fa mbchar
is not a null pointer,
.Fn mbtowc
either returns 0 if
.Fa mbchar
represents the null wide character, or returns
the number of bytes processed in
.Fa mbchar ,
or returns \-1 if no multibyte character
could be recognized or converted.
In this case,
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.Fn mbtowc Ns 's
internal conversion state is undefined.
.Sh ERRORS
The
.Fn mbtowc
function will fail if:
.Bl -tag -width Er
.It Bq Er EILSEQ
An invalid multibyte sequence was detected.
.It Bq Er EINVAL
The internal conversion state is invalid.
.El
.Sh SEE ALSO
.Xr btowc 3 ,
.Xr mblen 3 ,
.Xr mbrtowc 3 ,
.Xr mbstowcs 3 ,
.Xr multibyte 3 ,
.Xr wctomb 3
.Sh STANDARDS
The
.Fn mbtowc
function conforms to
.St -isoC-99 .