man-pages/man3/wcstombs.3.html
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<H1>WCSTOMBS</H1>
Section: Linux Programmer's Manual (3)<BR>Updated: 2019-03-06<BR><A HREF="#index">Index</A>
<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
<A NAME="lbAB">&nbsp;</A>
<H2>NAME</H2>
wcstombs - convert a wide-character string to a multibyte string
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<PRE>
<B>#include &lt;<A HREF="file:///usr/include/stdlib.h">stdlib.h</A>&gt;</B>
<B>size_t wcstombs(char *</B><I>dest</I><B>, const wchar_t *</B><I>src</I><B>, size_t </B><I>n</I><B>);</B>
</PRE>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
If
<I>dest</I>
is not NULL, the
<B>wcstombs</B>()
function converts
the wide-character string
<I>src</I>
to a multibyte string starting at
<I>dest</I>.
At most
<I>n</I>
bytes are written to
<I>dest</I>.
The sequence of characters placed in
<I>dest</I>
begins in the initial shift state.
The conversion can stop for three reasons:
<DL COMPACT>
<DT id="1">1.<DD>
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)&nbsp;-1</I>
is returned.
<DT id="2">2.<DD>
The length limit forces a stop.
In this case, the number of bytes written to
<I>dest</I>
is returned, but the shift state at this point is lost.
<DT id="3">3.<DD>
The wide-character string has been completely converted, including the
terminating null wide character (L'\0').
In this case, the conversion ends in the initial shift state.
The number of bytes written to
<I>dest</I>,
excluding the terminating null byte ('\0'), is returned.
</DL>
<P>
The programmer must ensure that there is room for at least
<I>n</I>
bytes
at
<I>dest</I>.
<P>
If
<I>dest</I>
is NULL,
<I>n</I>
is ignored, and the conversion proceeds as
above, except that the converted bytes are not written out to memory,
and no length limit exists.
<P>
In order to avoid the case 2 above, the programmer should make sure
<I>n</I>
is greater than or equal to
<I>wcstombs(NULL,src,0)+1</I>.
<A NAME="lbAE">&nbsp;</A>
<H2>RETURN VALUE</H2>
The
<B>wcstombs</B>()
function returns the number of bytes that make up the
converted part of a multibyte sequence,
not including the terminating null byte.
If a wide character was encountered which could not be
converted,
<I>(size_t)&nbsp;-1</I>
is returned.
<A NAME="lbAF">&nbsp;</A>
<H2>ATTRIBUTES</H2>
For an explanation of the terms used in this section, see
<B><A HREF="/cgi-bin/man/man2html?7+attributes">attributes</A></B>(7).
<TABLE BORDER>
<TR VALIGN=top><TD><B>Interface</B></TD><TD><B>Attribute</B></TD><TD><B>Value</B><BR></TD></TR>
<TR VALIGN=top><TD>
<B>wcstombs</B>()
</TD><TD>Thread safety</TD><TD>MT-Safe<BR></TD></TR>
</TABLE>
<P>
<A NAME="lbAG">&nbsp;</A>
<H2>CONFORMING TO</H2>
POSIX.1-2001, POSIX.1-2008, C99.
<A NAME="lbAH">&nbsp;</A>
<H2>NOTES</H2>
The behavior of
<B>wcstombs</B>()
depends on the
<B>LC_CTYPE</B>
category of the
current locale.
<P>
The function
<B><A HREF="/cgi-bin/man/man2html?3+wcsrtombs">wcsrtombs</A></B>(3)
provides a better interface to the same functionality.
<A NAME="lbAI">&nbsp;</A>
<H2>SEE ALSO</H2>
<B><A HREF="/cgi-bin/man/man2html?3+mblen">mblen</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+mbstowcs">mbstowcs</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+mbtowc">mbtowc</A></B>(3),
<B><A HREF="/cgi-bin/man/man2html?3+wcsrtombs">wcsrtombs</A></B>(3)
<B><A HREF="/cgi-bin/man/man2html?3+wctomb">wctomb</A></B>(3)
<A NAME="lbAJ">&nbsp;</A>
<H2>COLOPHON</H2>
This page is part of release 5.05 of the Linux
<I>man-pages</I>
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
<A HREF="https://www.kernel.org/doc/man-pages/.">https://www.kernel.org/doc/man-pages/.</A>
<P>
<HR>
<A NAME="index">&nbsp;</A><H2>Index</H2>
<DL>
<DT id="4"><A HREF="#lbAB">NAME</A><DD>
<DT id="5"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="6"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="7"><A HREF="#lbAE">RETURN VALUE</A><DD>
<DT id="8"><A HREF="#lbAF">ATTRIBUTES</A><DD>
<DT id="9"><A HREF="#lbAG">CONFORMING TO</A><DD>
<DT id="10"><A HREF="#lbAH">NOTES</A><DD>
<DT id="11"><A HREF="#lbAI">SEE ALSO</A><DD>
<DT id="12"><A HREF="#lbAJ">COLOPHON</A><DD>
</DL>
<HR>
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