Arc
Arc<T>
allows shared read-only access via Arc::clone
:
Speaker Notes
This slide should take about 5 minutes.
Arc
stands for "Atomic Reference Counted", a thread safe version ofRc
that uses atomic operations.Arc<T>
implementsClone
whether or notT
does. It implementsSend
andSync
if and only ifT
implements them both.Arc::clone()
has the cost of atomic operations that get executed, but after that the use of theT
is free.- Beware of reference cycles,
Arc
does not use a garbage collector to detect them.std::sync::Weak
can help.