| 1 | // |
|---|---|
| 2 | // Test that ref(ref(x)) does NOT collapse to ref(x) |
| 3 | // |
| 4 | // This irregularity of std::ref is questionable and breaks |
| 5 | // existing Boost code such as proto::make_expr |
| 6 | // |
| 7 | // Copyright 2014 Peter Dimov |
| 8 | // |
| 9 | // Distributed under the Boost Software License, Version 1.0. |
| 10 | // See accompanying file LICENSE_1_0.txt or copy at |
| 11 | // http://www.boost.org/LICENSE_1_0.txt |
| 12 | // |
| 13 | |
| 14 | #include <boost/core/ref.hpp> |
| 15 | #include <boost/core/lightweight_test.hpp> |
| 16 | |
| 17 | template<class T> void test( T const & t ) |
| 18 | { |
| 19 | { |
| 20 | boost::reference_wrapper< T const > r = boost::ref( t ); |
| 21 | BOOST_TEST_EQ( &r.get(), &t ); |
| 22 | } |
| 23 | |
| 24 | { |
| 25 | boost::reference_wrapper< T const > r = boost::cref( t ); |
| 26 | BOOST_TEST_EQ( &r.get(), &t ); |
| 27 | } |
| 28 | } |
| 29 | |
| 30 | template<class T> void test_nonconst( T & t ) |
| 31 | { |
| 32 | { |
| 33 | boost::reference_wrapper< T > r = boost::ref( t ); |
| 34 | BOOST_TEST_EQ( &r.get(), &t ); |
| 35 | } |
| 36 | |
| 37 | { |
| 38 | boost::reference_wrapper< T const > r = boost::cref( t ); |
| 39 | BOOST_TEST_EQ( &r.get(), &t ); |
| 40 | } |
| 41 | } |
| 42 | |
| 43 | int main() |
| 44 | { |
| 45 | int x = 0; |
| 46 | |
| 47 | test( t: x ); |
| 48 | test( t: boost::ref( t&: x ) ); |
| 49 | test( t: boost::cref( t: x ) ); |
| 50 | |
| 51 | test_nonconst( t&: x ); |
| 52 | |
| 53 | { |
| 54 | boost::reference_wrapper< int > r = boost::ref( t&: x ); |
| 55 | test_nonconst( t&: r ); |
| 56 | } |
| 57 | |
| 58 | { |
| 59 | boost::reference_wrapper< int const > r = boost::cref( t: x ); |
| 60 | test_nonconst( t&: r ); |
| 61 | } |
| 62 | |
| 63 | return boost::report_errors(); |
| 64 | } |
| 65 |