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 $
|
|
.\"
|
|
.\" 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 4, 2002
|
|
.Dt MBRTOWC 3
|
|
.Os
|
|
.\" ----------------------------------------------------------------------
|
|
.Sh NAME
|
|
.Nm mbrtowc
|
|
.Nd converts a multibyte character to a wide character (restartable)
|
|
.\" ----------------------------------------------------------------------
|
|
.Sh LIBRARY
|
|
.Lb libc
|
|
.\" ----------------------------------------------------------------------
|
|
.Sh SYNOPSIS
|
|
.In wchar.h
|
|
.Ft size_t
|
|
.Fn mbrtowc "wchar_t * restrict pwc" "const char * restrict s" "size_t n" \
|
|
"mbstate_t * restrict ps"
|
|
.\" ----------------------------------------------------------------------
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn mbrtowc
|
|
usually converts the multibyte character pointed to by
|
|
.Fa s
|
|
to a wide character, and stores the wide character
|
|
to the wchar_t object pointed to by
|
|
.Fa pwc
|
|
if
|
|
.Fa pwc
|
|
is
|
|
.Pf non- Dv NULL
|
|
and
|
|
.Fa s
|
|
points to a valid character.
|
|
The conversion happens in accordance with, and changes the conversion
|
|
state described in the mbstate_t object pointed to by
|
|
.Fa ps .
|
|
This function may examine at most
|
|
.Fa n
|
|
bytes of the array beginning from
|
|
.Fa s .
|
|
.Pp
|
|
If
|
|
.Fa s
|
|
points to a valid character and the character corresponds to a nul wide
|
|
character, then the
|
|
.Fn mbrtowc
|
|
places the mbstate_t object pointed to by
|
|
.Fa ps
|
|
to an initial conversion state.
|
|
.Pp
|
|
Unlike
|
|
.Xr mbtowc 3 ,
|
|
the
|
|
.Fn mbrtowc
|
|
may accept the byte sequence pointed to by
|
|
.Fa s
|
|
not forming a complete multibyte character
|
|
but which may be 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 at subsequent calls of this function to restart
|
|
the conversion suspended.
|
|
.Pp
|
|
The behaviour of
|
|
.Fn mbrtowc
|
|
is affected by the
|
|
.Dv LC_CTYPE
|
|
category of the current locale.
|
|
.Pp
|
|
These are the special cases:
|
|
.Bl -tag -width 012345678901
|
|
.It "s == NULL"
|
|
.Fn mbrtowc
|
|
sets the conversion state object pointed to by
|
|
.Fa ps
|
|
to an initial state and always returns 0.
|
|
Unlike
|
|
.Xr mbtowc 3 ,
|
|
the value returned does not indicate whether the current encoding of
|
|
the locale is state-dependent.
|
|
.Pp
|
|
In this case,
|
|
.Fn mbrtowc
|
|
ignores
|
|
.Fa pwc
|
|
and
|
|
.Fa n ,
|
|
and is equivalent to the following call:
|
|
.Bd -literal -offset indent
|
|
mbrtowc(NULL, "", 1, ps);
|
|
.Ed
|
|
.It "pwc == NULL"
|
|
The conversion from a multibyte character to a wide character has
|
|
taken place and the conversion state may be affected, but the resulting
|
|
wide character is discarded.
|
|
.It "ps == NULL"
|
|
.Fn mbrtowc
|
|
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 mbrtowc ,
|
|
which is initialized at startup time of the program.
|
|
.El
|
|
.\" ----------------------------------------------------------------------
|
|
.Sh RETURN VALUES
|
|
In the usual cases,
|
|
.Fn mbrtowc
|
|
returns:
|
|
.Bl -tag -width 012345678901
|
|
.It 0
|
|
The next bytes pointed to by
|
|
.Fa s
|
|
form a nul character.
|
|
.It positive
|
|
If
|
|
.Fa s
|
|
points to a valid character,
|
|
.Fn mbrtowc
|
|
returns the number of bytes in the character.
|
|
.It (size_t)-2
|
|
.Fa s
|
|
points to a 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 mbrtowc
|
|
may cause an error in the following case:
|
|
.Bl -tag -width Er
|
|
.It Bq Er EILSEQ
|
|
.Fa s
|
|
points to an invalid or incomplete multibyte character.
|
|
.It Bq Er EINVAL
|
|
.Fa ps
|
|
points to an invalid or uninitialized mbstate_t object.
|
|
.El
|
|
.\" ----------------------------------------------------------------------
|
|
.Sh SEE ALSO
|
|
.Xr mbrlen 3 ,
|
|
.Xr mbtowc 3 ,
|
|
.Xr setlocale 3
|
|
.\" ----------------------------------------------------------------------
|
|
.Sh STANDARDS
|
|
The
|
|
.Fn mbrtowc
|
|
function conforms to
|
|
.St -isoC-amd1 .
|
|
The restrict qualifier is added at
|
|
.St -isoC-99 .
|