pub type UpgradeIntoFn = for<'ptr> unsafe fn(_: PtrMut<'ptr>, _: PtrUninit<'ptr>) -> Option<PtrMut<'ptr>>;Expand description
Tries to upgrade the weak pointer to a strong one.
§Safety
weak must be a valid weak smart pointer (like std::sync::Weak or std::rc::Weak).
strong must be allocated, and of the right layout for the corresponding smart pointer.
strong must not have been initialized yet.
weak is not moved out of — Weak::upgrade(&self) takes self by reference.
If this fails, strong is not initialized.
strong.assume_init() is returned as part of the Option if the upgrade succeeds.
None is returned if this is not a type of smart pointer that supports upgrades.