20 lines
654 B
Rust
20 lines
654 B
Rust
#![feature(weak_into_raw)]
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use std::rc::{Rc, Weak};
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use std::ptr;
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/// Taken from the `Weak::as_raw` doctest.
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fn main() {
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let strong = Rc::new(Box::new(42));
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let weak = Rc::downgrade(&strong);
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// Both point to the same object
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assert!(ptr::eq(&*strong, Weak::as_raw(&weak)));
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// The strong here keeps it alive, so we can still access the object.
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assert_eq!(42, **unsafe { &*Weak::as_raw(&weak) });
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drop(strong);
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// But not any more. We can do Weak::as_raw(&weak), but accessing the pointer would lead to
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// undefined behaviour.
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assert_eq!(42, **unsafe { &*Weak::as_raw(&weak) }); //~ ERROR dangling pointer
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}
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