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.\" Copyright (c) Bruno Haible <haible@clisp.cons.org>
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.\" References consulted:
.\"   GNU glibc-2 source code and manual
.\"   Dinkumware C library reference http://www.dinkumware.com/
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.TH WCSTOMBS 3  2011-10-16 "GNU" "Linux Programmer's Manual"
.SH NAME
wcstombs \- convert a wide-character string to a multibyte string
.SH SYNOPSIS
.nf
.B #include <stdlib.h>
.sp
.BI "size_t wcstombs(char *" dest ", const wchar_t *" src ", size_t " n );
.fi
.SH DESCRIPTION
If \fIdest\fP is not a NULL pointer, the
.BR wcstombs ()
function converts
the wide-character string \fIsrc\fP to a multibyte string starting at
\fIdest\fP.
At most \fIn\fP bytes are written to \fIdest\fP.
The conversion
starts in the initial state.
The conversion can stop for three reasons:
.PP
1. A wide character has been encountered that can not be represented as a
multibyte sequence (according to the current locale).
In this case
.I (size_t)\ \-1
is returned.
.PP
2. The length limit forces a stop.
In this case the number of bytes written to
\fIdest\fP is returned, but the shift state at this point is lost.
.PP
3. The wide-character string has been completely converted, including the
terminating null wide character (L\(aq\\0\(aq).
In this case the conversion ends in the initial state.
The number of bytes written to \fIdest\fP,
excluding the terminating null byte (\(aq\\0\(aq), is returned.
.PP
The programmer must ensure that there is room for at least \fIn\fP bytes
at \fIdest\fP.
.PP
If \fIdest\fP is NULL, \fIn\fP is ignored, and the conversion proceeds as
above, except that the converted bytes are not written out to memory,
and that no length limit exists.
.PP
In order to avoid the case 2 above, the programmer should make sure \fIn\fP
is greater or equal to \fIwcstombs(NULL,src,0)+1\fP.
.SH RETURN VALUE
The
.BR wcstombs ()
function returns the number of bytes that make up the
converted part of multibyte sequence, not including the terminating null byte.
If a wide character was encountered which could not be
converted,
.I (size_t)\ \-1
is returned.
.SH CONFORMING TO
C99.
.SH NOTES
The behavior of
.BR wcstombs ()
depends on the
.B LC_CTYPE
category of the
current locale.
.PP
The function
.BR wcsrtombs (3)
provides a thread safe interface to
the same functionality.
.SH SEE ALSO
.BR mbstowcs (3),
.BR wcsrtombs (3)