@@ -948,6 +948,12 @@ requirements of the license of GCC.
<listitem><para>Update definitions of the partial specializations for const and volatile types.
</para></listitem></varlistentry>
+ <varlistentry><term><link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="../ext/lwg-defects.html#2328">2328</link>:
+ <emphasis>Rvalue stream extraction should use perfect forwarding</emphasis>
+ </term>
+ <listitem><para>Use perfect forwarding for right operand.
+ </para></listitem></varlistentry>
+
<varlistentry><term><link xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="../ext/lwg-defects.html#2329">2329</link>:
<emphasis><code>regex_match()/regex_search()</code> with <code>match_results</code> should forbid temporary strings</emphasis>
</term>
@@ -909,6 +909,8 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
#if __cplusplus >= 201103L
// [27.7.1.6] Rvalue stream extraction
+ // _GLIBCXX_RESOLVE_LIB_DEFECTS
+ // 2328. Rvalue stream extraction should use perfect forwarding
/**
* @brief Generic extractor for rvalue stream
* @param __is An input stream.
@@ -921,9 +923,9 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
*/
template<typename _CharT, typename _Traits, typename _Tp>
inline basic_istream<_CharT, _Traits>&
- operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp& __x)
+ operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp&& __x)
{
- __is >> __x;
+ __is >> std::forward<_Tp>(__x);
return __is;
}
#endif // C++11
@@ -34,9 +34,33 @@ test01()
VERIFY (i == i2);
}
+struct X { bool as_rvalue; };
+
+void operator>>(std::istream&, X& x) { x.as_rvalue = false; }
+void operator>>(std::istream&, X&& x) { x.as_rvalue = true; }
+
+// LWG 2328 Rvalue stream extraction should use perfect forwarding
+void
+test02()
+{
+ X x;
+ std::istringstream is;
+ auto& ref1 = (std::move(is) >> x);
+ VERIFY( &ref1 == &is );
+ VERIFY( x.as_rvalue == false );
+ auto& ref2 = (std::move(is) >> std::move(x));
+ VERIFY( &ref2 == &is );
+ VERIFY( x.as_rvalue == true );
+
+ char arr[2];
+ std::istringstream("x") >> &arr[0];
+ std::istringstream("x") >> arr;
+}
+
int
main()
{
test01();
+ test02();
return 0;
}
* include/std/istream (operator>>(basic_istream&&, _Tp&)): Adjust to use perfect forwarding (LWG 2328). * testsuite/27_io/rvalue_streams.cc: Test perfect forwarding. * doc/xml/manual/intro.xml: Document DR 2328 status. Teted x86_64-linux, committed to trunk. commit 8a9c61de6663071a562e90ce7d2a2b7a2228fd95 Author: Jonathan Wakely <jwakely@redhat.com> Date: Wed Oct 21 21:33:37 2015 +0100 LWG 2328 Rvalue stream extraction should use perfect forwarding * include/std/istream (operator>>(basic_istream&&, _Tp&)): Adjust to use perfect forwarding (LWG 2328). * testsuite/27_io/rvalue_streams.cc: Test perfect forwarding. * doc/xml/manual/intro.xml: Document DR 2328 status.