On 07/02/2017 02:49 AM, Shachar Shemesh wrote:
On 02/07/17 02:08, Andrei Alexandrescu wrote:
Vaguely related question: should "const" convert implicitly to "const
shared"? The intuition is that the latter offers even less guarantees
than the former so it's the more general type. See
http://erdani.com/conversions3.svg.
I don't see how it can. They provide different guarantees. If anything,
it should be the other way around.
If you hold a pointer to const, you know the data will not change during
the function's execution. No such guarantees for const shared.
That supports the case for allowing the conversion.
const: "You have a view to data that this thread may or may not change."
const shared: "You have a view to data that any thread may or may not
change."
So the set of const is included in the set of const shared - texbook
inclusion polymorphism.
Andrei
