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    <p>If you implement this with move operators there is a way:</p> <pre><code>Bar &amp; Bar :: operator = (Bar &amp;&amp; source) { this -&gt; ~ Bar (); new (this) Bar (std :: move (source)); return *this; } </code></pre> <p>You shouldn't really use this trick with copy constructors because they can often throw and then this isn't safe. Move constructors should never <em>ever</em> throw, so this should be OK.</p> <p><code>std::vector</code> and other containers now exploit move operations wherever possible, so resize and sort and so on will be OK.</p> <p>This approach will let you keep const and reference members but you still can't <em>copy</em> the object. To do that, you would have to use non-const and pointer members.</p> <p>And by the way, you should never use memcpy like that for non-POD types.</p> <h3>Edit</h3> <p>A response to the Undefined Behaviour complaint.</p> <p>The problem case seems to be</p> <pre><code>struct X { const int &amp; member; X &amp; operator = (X &amp;&amp;) { ... as above ... } ... }; X x; const int &amp; foo = x.member; X = std :: move (some_other_X); // foo is no longer valid </code></pre> <p>True it is undefined behaviour if you continue to use <code>foo</code>. To me this is the same as</p> <pre><code>X * x = new X (); const int &amp; foo = x.member; delete x; </code></pre> <p>in which it is quite clear that using <code>foo</code> is invalid.</p> <p>Perhaps a naive read of the <code>X::operator=(X&amp;&amp;)</code> would lead you to think that perhaps <code>foo</code> is still valid after a move, a bit like this</p> <pre><code>const int &amp; (X::*ptr) = &amp;X::member; X x; // x.*ptr is x.member X = std :: move (some_other_X); // x.*ptr is STILL x.member </code></pre> <p>The member pointer <code>ptr</code> survives the move of <code>x</code> but <code>foo</code> does not.</p>
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    1. POHow to copy (or swap) objects of a type that contains members that are references or const?
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    1. POHow to copy (or swap) objects of a type that contains members that are references or const?
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    1. COI think this works just fine for copying as well (slight syntax change) -- I don't think he meant to imply he doesn't want to be able to copy. I'm trying to figure out if placement new on this is valid for all types of objects, and if not, which ones?
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    2. COThis is close to what I'm after. Upvoted since I didn't say "C++03 only" in my question. Is there any way to do this without moving to C++11? (I don't have that luxury. Our code has to be compilable with a C++03 compiler.)
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    3. CORe *And by the way, you should never use memcpy like that for non-POD types.* I know that. I posted that mainly because code like that is rampant on the 'net; I didn't want someone offering it as a solution. My current implementation is option A, don't use references and const data members. Option B, invoke undefined behavior, is a non-starter to me. I would like Option C, the magical version that works in C++03, and does so without invoking option A and without invoking UB.
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