.\" $MirOS: src/lib/libc/locale/wcsrtombs.3,v 1.5 2014/02/09 22:35:55 tg Exp $
.\" $OpenBSD: wcsrtombs.3,v 1.1 2005/05/11 18:44:12 espie Exp $
.\" $NetBSD: wcsrtombs.3,v 1.6 2003/09/08 17:54:32 wiz Exp $
.\"
.\" Copyright (c)2002 Citrus Project,
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.Dd $Mdocdate: February 9 2014 $
.Dt WCSRTOMBS 3
.Os
.\" ----------------------------------------------------------------------
.Sh NAME
.Nm wcsrtombs ,
.Nm wcsnrtombs
.Nd convert a wide character string to a multibyte character string \
(restartable)
.\" ----------------------------------------------------------------------
.Sh SYNOPSIS
.Fd #include <stdlib.h>
.Ft size_t
.Fn wcsrtombs "char *s" "const wchar_t **pwcs" "size_t n" "mbstate_t *ps"
.Ft size_t
.Fn wcsnrtombs "char *s" "const wchar_t **pwcs" "size_t max" "size_t n" "mbstate_t *ps"
.\" ----------------------------------------------------------------------
.Sh DESCRIPTION
.Fn wcsrtombs
converts the null-terminated wide character string indirectly pointed to by
.Fa pwcs
to the corresponding multibyte character string,
and store it to the array pointed to by
.Fa s .
The
.Fn wcsnrtombs
function behaves the same, but reads at most
.Fa max
wide characters from the wide character string indirectly pointed to by
.Fa pwcs .
The conversion stops due to the following reasons:
.Bl -bullet
.It
The conversion reaches a null wide character.
In this case, the null wide character is also converted.
.It
.Fn wcsrtombs
or
.Fn wcsnrtombs
has already stored
.Fa n
bytes to the array pointed to by
.Fa s .
.It
The conversion encounters an invalid character.
.It
The
.Fn wcsnrtombs
function has already devoured
.Fa max
wide characters.
.El
.Pp
Each characters will be converted as if
.Xr wcrtomb 3
is continuously called, except the internal state of
.Xr wcrtomb 3
will not be affected.
.Pp
After conversion,
if
.Fa s
is not a
.Dv NULL
pointer,
the pointer object pointed to by
.Fa pwcs
is a
.Dv NULL
pointer (if the conversion is stopped due to reaching a null wide character)
or the first byte of the character just after the last character converted.
.Pp
If
.Fa s
is not a null pointer and the conversion is stopped due to reaching
a null wide character,
.Fn wcsrtombs
and
.Fn wcsnrtombs
place the state object pointed to by
.Fa ps
to an initial state after the conversion is taken place.
.Pp
The behaviour of the
.Fn wcsrtombs
and
.Fn wcsnrtombs
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 wcsrtombs
and
.Fn wcsnrtombs
return the number of bytes to store the whole multibyte character string
corresponding to the wide character string pointed to by
.Fa pwcs ,
not including the terminating null byte.
In this case,
.Fa n
is ignored.
.It "pwcs == NULL || *pwcs == NULL"
Undefined (may causes the program to crash).
.It "ps == NULL"
.Fn wcsrtombs
uses its own internal state object to keep the conversion state,
instead of
.Fa ps
mentioned in this manual page.
.Fn wcsnrtombs
has an own internal state which is different from the one of
.Fn wcsrtombs .
.Pp
Calling any other functions in
.Em libc
never change the internal
state of
.Fn wcsnrtombs
or
.Fn wcsrtombs ,
that is initialised at startup time of the program.
.El
.\" ----------------------------------------------------------------------
.Sh RETURN VALUES
.Fn wcsrtombs
and
.Fn wcsnrtombs
return:
.Bl -tag -width 012345678901
.It 0 or positive
Number of bytes stored to the array pointed to by
.Fa s ,
except for a null byte.
There is no cases that the value returned is greater than
.Fa n
(unless
.Fa s
is a null pointer).
If the return value is equal to
.Fa n ,
the string pointed to by
.Fa s
will not be null-terminated.
.It (size_t)-1
.Fa pwcs
points to the string containing invalid wide character.
.Fn wcsrtombs
and
.Fn wcsnrtombs
also set errno to indicate the error.
.El
.\" ----------------------------------------------------------------------
.Sh ERRORS
.Fn wcsrtombs
and
.Fn wcsnrtombs
may cause an error in the following cases:
.Bl -tag -width Er
.It Bq Er EILSEQ
.Fa pwcs
points to the string containing an invalid wide character.
.El
.\" ----------------------------------------------------------------------
.Sh SEE ALSO
.Xr optu16to8 3 ,
.Xr setlocale 3 ,
.Xr wcrtomb 3 ,
.Xr wcstombs 3
.\" ----------------------------------------------------------------------
.Sh STANDARDS
The
.Fn wcsrtombs
function conforms to
.St -ansiC .
The
.Fn wcsnrtombs
function is a GNU extension.
.Sh HISTORY
.Fn wcsnrtombs
first appeared in
.Mx 10 .