Implement LWG2328. Rvalue stream extraction should perfect forward.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@276545 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Eric Fiselier
2016-07-24 04:07:22 +00:00
parent c672a7453d
commit 7f630e8ffa
3 changed files with 18 additions and 9 deletions

View File

@@ -1481,9 +1481,9 @@ ws(basic_istream<_CharT, _Traits>& __is)
template <class _CharT, class _Traits, class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
basic_istream<_CharT, _Traits>&
operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp& __x)
operator>>(basic_istream<_CharT, _Traits>&& __is, _Tp&& __x)
{
__is >> __x;
__is >> _VSTD::forward<_Tp>(__x);
return __is;
}

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@@ -7,17 +7,18 @@
//
//===----------------------------------------------------------------------===//
// UNSUPPORTED: c++98, c++03
// <istream>
// template <class charT, class traits, class T>
// basic_istream<charT, traits>&
// operator>>(basic_istream<charT, traits>&& is, T& x);
// operator>>(basic_istream<charT, traits>&& is, T&& x);
#include <istream>
#include <sstream>
#include <cassert>
#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
template <class CharT>
struct testbuf
: public std::basic_streambuf<CharT>
@@ -42,11 +43,13 @@ public:
CharT* egptr() const {return base::egptr();}
};
#endif // _LIBCPP_HAS_NO_RVALUE_REFERENCES
struct A{};
bool called = false;
void operator>>(std::istream&, A&&){ called = true; }
int main()
{
#ifndef _LIBCPP_HAS_NO_RVALUE_REFERENCES
{
testbuf<char> sb(" 123");
int i = 0;
@@ -59,5 +62,11 @@ int main()
std::wistream(&sb) >> i;
assert(i == 123);
}
#endif // _LIBCPP_HAS_NO_RVALUE_REFERENCES
{ // test perfect forwarding
assert(called == false);
std::istringstream ss;
auto& out = (std::move(ss) >> A{});
assert(&out == &ss);
assert(called);
}
}

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@@ -264,7 +264,7 @@
<tr><td><a href="http://wg21.link/LWG2309">2309</a></td><td>mutex::lock() should not throw device_or_resource_busy</td><td>Oulu</td><td>Complete</td></tr>
<tr><td><a href="http://wg21.link/LWG2310">2310</a></td><td>Public exposition only member in std::array</td><td>Oulu</td><td>Complete</td></tr>
<tr><td><a href="http://wg21.link/LWG2312">2312</a></td><td>tuple's constructor constraints need to be phrased more precisely</td><td>Oulu</td><td>Complete</td></tr>
<tr><td><a href="http://wg21.link/LWG2328">2328</a></td><td>Rvalue stream extraction should use perfect forwarding</td><td>Oulu</td><td></td></tr>
<tr><td><a href="http://wg21.link/LWG2328">2328</a></td><td>Rvalue stream extraction should use perfect forwarding</td><td>Oulu</td><td>Complete</td></tr>
<tr><td><a href="http://wg21.link/LWG2393">2393</a></td><td>std::function's Callable definition is broken</td><td>Oulu</td><td></td></tr>
<tr><td><a href="http://wg21.link/LWG2422">2422</a></td><td>std::numeric_limits&lt;T&gt;::is_modulo description: "most machines" errata</td><td>Oulu</td><td>Complete</td></tr>
<tr><td><a href="http://wg21.link/LWG2426">2426</a></td><td>Issue about compare_exchange</td><td>Oulu</td><td></td></tr>