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weak reference

A pointer to a shared value that doesn't keep the value alive.

Weak (from Rc::downgrade) doesn't raise the strong count; upgrade() returns Some(Rc) while the value lives and None after it's freed.

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Examples

  • let w = Rc::downgrade(&theme); then w.upgrade() is Some(..) while theme lives and None after the last Rc is dropped.

See also

reference counting reference cycle smart pointer
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