copy assignable - what exactly is it?

[Doug Mika]

It says that the atomic bool is not copy-assignable, however, you can assign to it a bool value:

atomic<bool> b(true);
b=false; //assignment operation which relies on the overloaded copy assignment operator.

What is copy assignable and which operator does it rely on?

[Bo Persson]

You are assigning a value, which is not a copy of an atomic variable.
Copy assign means assigning a value of the same type. Atomic types have
these operators deleted, to make them non-copyable.

atomic(const atomic&) = delete;
atomic& operator=(const atomic&) = delete;
atomic& operator=(const atomic&) volatile = delete;


Bo Persson

[Doug Mika]

so which operator is used to assign a bool to an atomic, as in my case above?

[Ian Collins]

atomic& operator=( T );

--
Ian Collins

[Juha Nieminen]

"Copy-assignable" means that you can assign one instance to another. In other words:

std::atomic<bool> a(true), b(true);
a = b; // error

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[Vir Campestris]

On 11/08/2015 09:10, Juha Nieminen wrote:
> "Copy-assignable" means that you can assign one instance to another. In other words:
>
> std::atomic<bool> a(true), b(true);
> a = b; // error

Presumably a = static_cast<bool>(b); would work - extracting to a
non-atomic in the middle?

It would not of course be atomic...

Andy