3 ms·

Can someone explain where the stackless/stackful naming comes from and what does it mean?

• dgroshev 3y ago
  Rust futures don't have stacks, all local variables get translated into struct fields, so suspending execution on an awake point is trivial, you just start executing another future. It also means there is no need for a runtime for a future to make sense (it's just a struct with a trait implemented) and the futures are completely static and amenable to compiler optimisations like inlining. On the other hand, it means that the structure is by necessity self referential (one "local" variable might refer to another, so the struct has addresses in it), which means it can't be safely moved (because will point at the old address). "Stackful" coroutines, on the other hand, do have runtime stacks (holding local variables) that get swapped out by the runtime on await points. It makes the code behave exactly like non-async code, but requires a runtime to manage those stacks. Rust didn't go this way, preferring the benefits of the stackless approach.