NetBSD/lib/libc/locale/mbstowcs.3

.\" $NetBSD: mbstowcs.3,v 1.8 2004/01/24 16:58:54 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 3, 2002
.Dt MBSTOWCS 3
.Os
.\" ----------------------------------------------------------------------
.Sh NAME
.Nm mbstowcs
.Nd converts a multibyte character string to a wide character string
.\" ----------------------------------------------------------------------
.Sh LIBRARY
.Lb libc
.\" ----------------------------------------------------------------------
.Sh SYNOPSIS
.In stdlib.h
.Ft size_t
.Fn mbstowcs "wchar_t * restrict pwcs" "const char * restrict s" "size_t n"
.\" ----------------------------------------------------------------------
.Sh DESCRIPTION
.Fn mbstowcs
converts a null-terminated multibyte character string pointed to by
.Fa s
to the corresponding wide character string and stores it in the array
pointed to by
.Fa pwcs .
This function may modify the first at most
.Fa n
elements of the array pointed to by
.Fa pwcs .
Each character will be converted as if
.Xr mbtowc 3
is continuously called, except the internal state of
.Xr mbtowc 3
will not be affected.
.Pp
For state-dependent encoding,
.Fn mbstowcs
implies the multibyte character string pointed to by
.Fa s
always begins with an initial state.
.Pp
These are the special cases:
.Bl -tag -width 012345678901
.It pwcs == NULL
.Fn mbstowcs
returns the number of elements to store the whole wide character string
corresponding to the multibyte character string pointed to by
.Fa s .
In this case,
.Fa n
is ignored.
.It s == NULL
Undefined (may cause the program to crash).
.El
.\" ----------------------------------------------------------------------
.Sh RETURN VALUES
.Fn mbstowcs
returns:
.Bl -tag -width 012345678901
.It 0 or positive
Number of elements stored in the array pointed to by
.Fa pwcs .
There are no cases that the value returned is greater than
.Fa n
(unless
.Fa pwcs
is a null pointer) or the value of the
.Dv MB_CUR_MAX
macro.
If the return value is equal to
.Fa n ,
the string pointed to by
.Fa pwcs
will not be null-terminated.
.It (size_t)-1
.Fa s
points to a string containing an invalid or incomplete multibyte character.
The
.Fn mbstowcs
also sets
.Va errno
to indicate the error.
.El
.\" ----------------------------------------------------------------------
.Sh ERRORS
.Fn mbstowcs
may cause an error in the following case:
.Bl -tag -width Er
.It Bq Er EILSEQ
.Fa s
points to a string containing an invalid or incomplete multibyte character.
.El
.\" ----------------------------------------------------------------------
.Sh SEE ALSO
.Xr mbtowc 3 ,
.Xr setlocale 3
.\" ----------------------------------------------------------------------
.Sh STANDARDS
The
.Fn mbstowcs
function conforms to
.St -ansiC .
The restrict qualifier is added at
.St -isoC-99 .