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Volatile copyable not trivially copyable?

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Given a POD struct type, say  struct S { int a; };
it was always the case that if you wanted to be able to
assign to a volatile S, you had to explicitly define a
volatile-qualified copy-assignment operator:
   operator=(S const&) volatile;
But this makes S "not trivially copyable".  And in C++11
that means you can't instantiate std::atomic<S>.

Have I missed something?  It seems strange that if I
want to wrap a primitive type in a class for abstraction
reasons (in an OS maybe) the class can either be
volatile-qualified and assigned freely, or used as the
basis for an atomic type, but not both.  After all, there's
no such restriction on primitive types.

As a constructive suggestion, would there be any
consequences if the standard were to permit defining
   operator=(S cv-qualifiers&) volatile = default;
and consider it a trivial copy assignment operator?


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Volatile copyable not trivially copyable? Al Grant<algrant@myrealbox.com> - 2012-03-24 17:55 -0700
  Re: Volatile copyable not trivially copyable? Daniel Krügler <daniel.kruegler@googlemail.com> - 2012-03-25 23:14 -0700

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