NetBSD/lib/libc/locale/wctomb.3

.\" $NetBSD: wctomb.3,v 1.2 2002/03/18 07:56:30 wiz Exp $
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.Dd February 3, 2002
.Dt WCTOMB 3
.Os
.Sh NAME
.Nm wctomb
.Nd converts a wide character to a multibyte character
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.Fd #include \*[Lt]stdlib.h\*[Gt]
.Ft int
.Fn wctomb "char * s" "const wchar_t wchar"
.Sh DESCRIPTION
The
.Fn wctomb
converts the wide character
.Fa wchar
to the corresponding multibyte character, and store it to the array
pointed by
.Fa s .
The
.Fn wctomb
may store at most MB_CUR_MAX bytes to the array.
.Pp
In state-dependent encoding,
the
.Fn wctomb
may store the special sequence to change the conversion state
before an actual multibyte character into the array pointed
.Fa s .
If
.Fa wchar
is null wide character (L\'\\0\'),
this function places its own internal state to an initial conversion state.
.Pp
Calling any other functions in the
.Lb libc
never change the internal
state of the
.Fn wctomb ,
except for calling
.Xr setlocale 3
with changing LC_CTYPE category of the current locale.
Such
.Xr setlocale 3
call causes the internal state of this function to be indeterminate.
.Pp
The behaviour of the
.Fn wctomb
is affected by LC_CTYPE category of the current locale.
.Pp
There is a special case:
.Bl -tag -width 012345678901
.It s == NULL
.Fn wctomb
initializes its own internal state to an initial state, and
determines whether the current encoding is state-dependent.
This function returns 0 if the encoding is state-independent,
otherwise non-zero.
In this case,
.Fa wchar
is completely ignored.
.El
.Sh RETURN VALUES
In the usual case, the
.Fn wctomb
returns:
.Bl -tag -width 012345678901
.It positive
number of bytes for the valid multibyte character pointed by
.Fa s .
There is no cases that the value returned is greater than
.Fa n
or the value of MB_CUR_MAX macro.
.It -1
.Fa wchar
is an invalid wide character.
.El
.Pp
In the case that
.Fa s
is equal to NULL, the
.Fn mbtowc
returns:
.Bl -tag -width 0123456789
.It 0
The current encoding is state-independent.
.It non-zero
The current encoding is state-dependent.
.El
.Sh ERRORS
No errors are defined.
.Sh SEE ALSO
.Xr setlocale 3
.Sh STANDARDS
The
.Fn wctomb
function conforms to
.St -ansiC .