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.
207 lines
5.6 KiB
Groff
207 lines
5.6 KiB
Groff
.\" $NetBSD: mbrlen.3,v 1.9 2008/02/28 19:36:51 tnozaki Exp $
|
|
.\"
|
|
.\" Copyright (c)2002 Citrus Project,
|
|
.\" 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.
|
|
.\"
|
|
.Dd February 3, 2002
|
|
.Dt MBRLEN 3
|
|
.Os
|
|
.\" ----------------------------------------------------------------------
|
|
.Sh NAME
|
|
.Nm mbrlen
|
|
.Nd get number of bytes in a multibyte 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 usually determines the number of bytes in
|
|
a multibyte character pointed to by
|
|
.Fa s
|
|
and returns it.
|
|
This function shall only examine max n bytes of the array beginning from
|
|
.Fa s .
|
|
.Pp
|
|
.Fn mbrlen
|
|
is equivalent to the following call (except
|
|
.Fa ps
|
|
is evaluated only once):
|
|
.Bd -literal -offset indent
|
|
mbrtowc(NULL, s, n, (ps != NULL) ? ps : \*[Am]internal);
|
|
.Ed
|
|
.Pp
|
|
Here,
|
|
.Fa internal
|
|
is an internal state object.
|
|
.Pp
|
|
In state-dependent encodings,
|
|
.Fa s
|
|
may point to the special sequence bytes to change the shift-state.
|
|
Although such sequence bytes corresponds to no individual
|
|
wide-character code, these affect the conversion state object pointed
|
|
to by
|
|
.Fa ps ,
|
|
and the
|
|
.Fn mbrlen
|
|
treats the special sequence bytes
|
|
as if these are a part of the subsequent multibyte character.
|
|
.Pp
|
|
Unlike
|
|
.Xr mblen 3 ,
|
|
.Fn mbrlen
|
|
may accept the byte sequence when it is not a complete character
|
|
but possibly contains part of a valid character.
|
|
In this case, this function will accept all such bytes
|
|
and save them into the conversion state object pointed to by
|
|
.Fa ps .
|
|
They will be used on subsequent calls of this function to restart
|
|
the conversion suspended.
|
|
.Pp
|
|
The behaviour of
|
|
.Fn mbrlen
|
|
is affected by the
|
|
.Dv LC_CTYPE
|
|
category of the current locale.
|
|
.Pp
|
|
These are the special cases:
|
|
.Bl -tag -width 0123456789
|
|
.It "s == NULL"
|
|
.Fn mbrlen
|
|
sets the conversion state object pointed to by
|
|
.Fa ps
|
|
to an initial state and always returns 0.
|
|
Unlike
|
|
.Xr mblen 3 ,
|
|
the value returned does not indicate whether the current encoding of
|
|
the locale is state-dependent.
|
|
.Pp
|
|
In this case,
|
|
.Fn mbrlen
|
|
ignores
|
|
.Fa n .
|
|
.It "n == 0"
|
|
In this case,
|
|
the first
|
|
.Fa n
|
|
bytes of the array pointed to by
|
|
.Fa s
|
|
never form a complete character.
|
|
Thus,
|
|
.Fn mbrlen
|
|
always returns (size_t)-2.
|
|
.It "ps == NULL"
|
|
.Fn mbrlen
|
|
uses its own internal state object to keep the conversion state,
|
|
instead of
|
|
.Fa ps
|
|
mentioned in this manual page.
|
|
.Pp
|
|
Calling any other functions in
|
|
.Lb libc
|
|
never changes the internal
|
|
state of
|
|
.Fn mbrlen ,
|
|
except for calling
|
|
.Xr setlocale 3
|
|
with a changing
|
|
.Dv LC_CTYPE
|
|
category of the current locale.
|
|
Such
|
|
.Xr setlocale 3
|
|
calls cause the internal state of this function to be indeterminate.
|
|
This internal state is initialized at startup time of the program.
|
|
.El
|
|
.\" ----------------------------------------------------------------------
|
|
.Sh RETURN VALUES
|
|
The
|
|
.Fn mbrlen
|
|
returns:
|
|
.Bl -tag -width 0123456789
|
|
.It "0"
|
|
.Fa s
|
|
points to a nul byte
|
|
.Pq Sq \e0 .
|
|
.It "positive"
|
|
The value returned is
|
|
a number of bytes for the valid multibyte character pointed to by
|
|
.Fa s .
|
|
There are no cases that this value is greater than
|
|
.Fa n
|
|
or the value of the
|
|
.Dv MB_CUR_MAX
|
|
macro.
|
|
.It "(size_t)-2"
|
|
.Fa s
|
|
points to the byte sequence which possibly contains part of a valid
|
|
multibyte character, but which is incomplete.
|
|
When
|
|
.Fa n
|
|
is at least
|
|
.Dv MB_CUR_MAX ,
|
|
this case can only occur if the array pointed to by
|
|
.Fa s
|
|
contains a redundant shift sequence.
|
|
.It "(size_t)-1"
|
|
.Fa s
|
|
points to an illegal byte sequence which does not form a valid multibyte
|
|
character.
|
|
In this case,
|
|
.Fn mbrtowc
|
|
sets
|
|
.Va errno
|
|
to indicate the error.
|
|
.El
|
|
.\" ----------------------------------------------------------------------
|
|
.Sh ERRORS
|
|
.Fn mbrlen
|
|
may cause an error in the following case:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EILSEQ
|
|
.Fa s
|
|
points to an invalid multibyte character.
|
|
.It Bq Er EINVAL
|
|
.Fa ps
|
|
points to an invalid or uninitialized mbstate_t object.
|
|
.El
|
|
.\" ----------------------------------------------------------------------
|
|
.Sh SEE ALSO
|
|
.Xr mblen 3 ,
|
|
.Xr mbrtowc 3 ,
|
|
.Xr setlocale 3
|
|
.\" ----------------------------------------------------------------------
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn mbrlen
|
|
function conforms to
|
|
.St -isoC-amd1 .
|
|
The restrict qualifier is added at
|
|
.St -isoC-99 .
|