blob: 9a8b84ce51dd48147f4180cfe35d3b72e4f40a55 [file] [log] [blame]
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file distributed
with this work for additional information regarding copyright
ownership. The ASF licenses this file to you under the Apache
License, Version 2.0 (the License); you may not use this file
except in compliance with the License. You may obtain a copy of
the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
implied. See the License for the specific language governing
permissions and limitations under the License.
Copyright 1999-2007 Rogue Wave Software, Inc.
-->
<HTML>
<HEAD>
<TITLE>wcin</TITLE>
<LINK REL=StyleSheet HREF="../rw.css" TYPE="text/css" TITLE="Apache stdcxx Stylesheet"></HEAD>
<BODY BGCOLOR=#FFFFFF>
<A HREF="wcerr.html"><IMG SRC="images/bprev.gif" WIDTH=20 HEIGHT=21 ALT="Previous file" BORDER=O></A><A HREF="noframes.html"><IMG SRC="images/btop.gif" WIDTH=56 HEIGHT=21 ALT="Top of Document" BORDER=O></A><A HREF="booktoc.html"><IMG SRC="images/btoc.gif" WIDTH=56 HEIGHT=21 ALT="Contents" BORDER=O></A><A HREF="tindex.html"><IMG SRC="images/bindex.gif" WIDTH=56 HEIGHT=21 ALT="Index page" BORDER=O></A><A HREF="wclog.html"><IMG SRC="images/bnext.gif" WIDTH=25 HEIGHT=21 ALT="Next file" BORDER=O></A><DIV CLASS="DOCUMENTNAME"><B>Apache C++ Standard Library Reference Guide</B></DIV>
<H2>wcin</H2>
<P><B>Library:</B>&nbsp;&nbsp;<A HREF="2-11.html">Input/output</A></P><UL>
<LI><A HREF="#sec1">Local Index</A></LI>
<LI><A HREF="#sec2">Summary</A></LI>
<LI><A HREF="#sec3">Synopsis</A></LI>
<LI><A HREF="#sec4">Description</A></LI>
<LI><A HREF="#sec5">Warnings</A></LI>
<LI><A HREF="#sec6">See Also</A></LI>
<LI><A HREF="#sec7">Standards Conformance</A></LI>
</UL>
<A NAME="sec1"><H3>Local Index</H3></A>
No Entries
<A NAME="sec2"><H3>Summary</H3></A>
<P>A predefined stream that controls input from a stream buffer associated with the object <SAMP>stdin</SAMP> declared in <SAMP>&lt;cstdio&gt;</SAMP></P>
<A NAME="sec3"><H3>Synopsis</H3></A>
<PRE>#include &lt;iostream&gt;
namespace std {
extern wistream wcin;
}
</PRE>
<A NAME="sec4"><H3>Description</H3></A>
<P>The object <SAMP>wcin</SAMP> controls input from a stream buffer associated with the object <SAMP>stdin</SAMP> declared in <SAMP>&lt;cstdio&gt;.</SAMP> By default the standard C and C++ streams are synchronized, but performance improvement can be achieved by using the <B><I><A HREF="ios-base.html">ios_base</A></I></B> member function <SAMP>synch_with_stdio</SAMP> to desynchronize them. </P>
<P>After the object <SAMP>wcin</SAMP> is initialized, <SAMP>wcin.tie()</SAMP> returns <SAMP>&amp;wcout</SAMP>, which implies that <SAMP>wcin</SAMP> and <SAMP>wcout</SAMP> are synchronized. <SAMP>wcin</SAMP> uses the locale <B><I><A HREF="codecvt.html">codecvt</A></I></B> facet to convert the tiny characters extracted from <SAMP>stdin</SAMP> to the wide characters stored in the <SAMP>wcin</SAMP> buffer. </P>
<A NAME="sec5"><H3>Warnings</H3></A>
<P>Keep in mind that while the manipulator <SAMP>endl</SAMP> flushes the stream buffer, outputting the character <SAMP>L'\n'</SAMP> is <I>not</I> guaranteed to flush the stream buffer. You should output the <SAMP>L'\n'</SAMP> character without <SAMP>endl</SAMP> only if you do not need the buffer flushed. Note that outputting the <SAMP>L'\n'</SAMP> character in such cases, and hence not forcing a buffer flush, may result in a performance improvement. It greatly improves performance when C and C++ streams are not synchronized.</P>
<A NAME="sec6"><H3>See Also</H3></A>
<P><B><I><A HREF="basic-istream.html">basic_istream</A></I></B>, <B><I><A HREF="basic-iostream.html">basic_iostream</A></I></B>, <B><I><A HREF="basic-filebuf.html">basic_filebuf</A></I></B>, <B><I><A HREF="cin.html">cin</A></I></B>, <B><I><A HREF="cout.html">cout</A></I></B>, <B><I><A HREF="cerr.html">cerr</A></I></B>, <B><I><A HREF="clog.html">clog</A></I></B>, <B><I><A HREF="wcout.html">wcout</A></I></B>, <B><I><A HREF="wcerr.html">wcerr</A></I></B>, <B><I><A HREF="wclog.html">wclog</A></I></B>, <B><I><A HREF="ios-base.html">ios_base</A></I></B>, <B><I><A HREF="basic-ios.html">basic_ios</A></I></B></P>
<A NAME="sec7"><H3>Standards Conformance</H3></A>
<P><I>ISO/IEC 14882:1998 -- International Standard for Information Systems --Programming Language C++, Section 27.3.2</I></P>
<BR>
<HR>
<A HREF="wcerr.html"><IMG SRC="images/bprev.gif" WIDTH=20 HEIGHT=21 ALT="Previous file" BORDER=O></A><A HREF="noframes.html"><IMG SRC="images/btop.gif" WIDTH=56 HEIGHT=21 ALT="Top of Document" BORDER=O></A><A HREF="booktoc.html"><IMG SRC="images/btoc.gif" WIDTH=56 HEIGHT=21 ALT="Contents" BORDER=O></A><A HREF="tindex.html"><IMG SRC="images/bindex.gif" WIDTH=56 HEIGHT=21 ALT="Index page" BORDER=O></A><A HREF="wclog.html"><IMG SRC="images/bnext.gif" WIDTH=20 HEIGHT=21 ALT="Next file" BORDER=O></A>
<!-- Google Analytics tracking code -->
<script src="http://www.google-analytics.com/urchin.js" type="text/javascript">
</script>
<script type="text/javascript">
_uacct = "UA-1775151-1";
urchinTracker();
</script>
<!-- end of Google Analytics tracking code -->
</BODY>
</HTML>