NetBSD/lib/libc/locale/mbstowcs.3

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.\" $NetBSD: mbstowcs.3,v 1.3 2002/03/25 20:01:22 yamt 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.
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.\" 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
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.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
.Fd #include \*[Lt]stdlib.h\*[Gt]
.Ft size_t
.Fn mbstowcs "wchar_t * restrict pwcs" "const char * restrict s" "size_t n"
.\" ----------------------------------------------------------------------
.Sh DESCRIPTION
The
.Fn mbstowcs
converts a null-terminated multibyte character string pointed by
.Fa s
to the corresponding wide character string and stores it to the array
pointed by
.Fa pwcs .
This function may modify the first at most
.Fa n
elements of the array pointed by
.Fa pwcs .
Each characters 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, the
.Fn mbstowcs
implies the multibyte character string pointed by
.Fa s
always to begin with an initial state.
.Pp
There are special cases:
.Bl -tag -width 012345678901
.It pwcs == NULL
The
.Fn mbstowcs
returns the number of elements to store the whole wide character string
corresponding to the multibyte character string pointed by
.Fa s .
In this case,
.Fa n
is ignored.
.It s == NULL
undefined (may causes the program to crash).
.El
.\" ----------------------------------------------------------------------
.Sh RETURN VALUES
The
.Fn mbstowcs
returns:
.Bl -tag -width 012345678901
.It 0 or positive
Number of elements stored to the array pointed by
.Fa pwcs .
There is no cases that the value returned is greater than
.Fa n
(unless
.Fa pwcs
is a null pointer) or the value of MB_CUR_MAX macro.
If the return value is equal to
.Fa n ,
the string pointed by
.Fa pwcs
will not be null-terminated.
.It (size_t)-1
.Fa s
points the string containing invalid or incomplete multibyte character.
The
.Fn mbstowcs
also sets errno to indicate the error.
.El
.\" ----------------------------------------------------------------------
.Sh ERRORS
The
.Fn mbstowcs
may causes an error in the following case:
.Bl -tag -width Er
.It Bq Er EILSEQ
.Fa s
points the string containing 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 -isoC99 .