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

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.\" Copyright (c) 2002 Tim J. Robbins
.\" All rights reserved.
.\"
.\" 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.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR 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 AUTHOR 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.
.\"
.\" $FreeBSD$
.Dd August 16, 2002
.Dt MBRLEN 3
.Os
.Sh NAME
.Nm mbrlen
.Nd "get number of bytes in a character (restartable)"
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In wchar.h
.Ft size_t
.Fn mbrlen "const char *restrict s" "size_t n" "mbstate_t *restrict ps"
.Sh DESCRIPTION
The
.Fn mbrlen
function determines the the number of bytes constituting the
multibyte character sequence pointer to by
.Fa s .
.Pp
It is equivalent to:
.Pp
.Dl "mbrtowc(NULL, s, n, ps);"
.Pp
Except that when
.Fa ps
is a NULL pointer,
.Fn mbrlen
uses its own static, internal
.Ft mbstate_t
object to keep track of shift state.
.Sh RETURN VALUES
The
.Fn mbrlen
functions returns:
.Bl -tag -width indent
.It 0
The first
.Fa n
or fewer bytes of
.Fa s
represent the null wide character (L'\e0').
.It >0
The first
.Fa n
or fewer bytes of
.Fa s
represent a valid character,
.Fn mbrtowc
returns the length (in bytes) of the multibyte sequence.
.It Xo
.No ( Ns
.Ft size_t Ns
.No ) Ns \&-2
.Xc
The first
.Fa n
bytes of
.Fa s
are an incomplete multibyte sequence.
.It Xo
.No ( Ns
.Ft size_t Ns
.No ) Ns \&-1
.Xc
The byte sequence pointed to by
.Fa s
is an invalid multibyte sequence.
.El
.Sh ERRORS
The
.Fn mbrlen
function will fail if:
.Bl -tag -width Er
.\".It Bq Er EINVAL
.\"Invalid argument.
.It Bq Er EILSEQ
An invalid multibyte sequence was detected.
.El
.Sh SEE ALSO
.Xr mblen 3 ,
.Xr mbrtowc 3
.Sh STANDARDS
The
.Fn mbrlen
function conforms to
.St -isoC-99 .
.Sh BUGS
The current implementation does not support shift states.