reference-counting

问题 I've got a highly complex class : class C: pass And I've got this test code : for j in range(10): c = C() print c Which gives : <__main__.C instance at 0x7f7336a6cb00> <__main__.C instance at 0x7f7336a6cab8> <__main__.C instance at 0x7f7336a6cb00> <__main__.C instance at 0x7f7336a6cab8> <__main__.C instance at 0x7f7336a6cb00> <__main__.C instance at 0x7f7336a6cab8> <__main__.C instance at 0x7f7336a6cb00> <__main__.C instance at 0x7f7336a6cab8> <__main__.C instance at 0x7f7336a6cb00> <__main__

来源： https://stackoverflow.com/questions/63966103/how-to-tell-when-a-variable-goes-out-of-scope

来源： https://stackoverflow.com/questions/55361657/stdshared-ptr-calls-non-default-deleter-on-null-pointer

来源： https://stackoverflow.com/questions/55361657/stdshared-ptr-calls-non-default-deleter-on-null-pointer

问题 Please explain the Serde rc feature Opt into impls for Rc<T> and Arc<T> . Serializing and deserializing these types does not preserve identity and may result in multiple copies of the same data. Be sure that this is what you want before enabling this feature. Serializing a data structure containing reference-counted pointers will serialize a copy of the inner value of the pointer each time a pointer is referenced within the data structure. Serialization will not attempt to deduplicate these

问题 Please explain the Serde rc feature Opt into impls for Rc<T> and Arc<T> . Serializing and deserializing these types does not preserve identity and may result in multiple copies of the same data. Be sure that this is what you want before enabling this feature. Serializing a data structure containing reference-counted pointers will serialize a copy of the inner value of the pointer each time a pointer is referenced within the data structure. Serialization will not attempt to deduplicate these

问题 In purely functional languages, data is immutable. With reference counting, creating a reference cycle requires changing already created data. It seems like purely functional languages could use reference counting without worrying about the possibility of cycles. Am is right? If so, why don't they? I understand that reference counting is slower than GC in many cases, but at least it reduces pause times. It would be nice to have the option to use reference counting in cases where pause times

问题 In purely functional languages, data is immutable. With reference counting, creating a reference cycle requires changing already created data. It seems like purely functional languages could use reference counting without worrying about the possibility of cycles. Am is right? If so, why don't they? I understand that reference counting is slower than GC in many cases, but at least it reduces pause times. It would be nice to have the option to use reference counting in cases where pause times

问题 Here's an example: use std::rc::Rc; #[derive(PartialEq, Eq)] struct MyId; pub fn main() { let rc_a_0 = Rc::new(MyId); let rc_a_1 = rc_a_0.clone(); let rc_b_0 = Rc::new(MyId); let rc_b_1 = rc_b_0.clone(); println!("rc_a_0 == rc_a_1: {:?}", rc_a_0 == rc_a_1); println!("rc_a_0 == rc_b_0: {:?}", rc_a_0 == rc_b_0); } Both println! s above print true . Is there a way distinguish between the rc_a_* and rc_b_* pointers? 回答1: You can cast &*rc to *const T to get a pointer to the underlying data and

问题 Here's an example: use std::rc::Rc; #[derive(PartialEq, Eq)] struct MyId; pub fn main() { let rc_a_0 = Rc::new(MyId); let rc_a_1 = rc_a_0.clone(); let rc_b_0 = Rc::new(MyId); let rc_b_1 = rc_b_0.clone(); println!("rc_a_0 == rc_a_1: {:?}", rc_a_0 == rc_a_1); println!("rc_a_0 == rc_b_0: {:?}", rc_a_0 == rc_b_0); } Both println! s above print true . Is there a way distinguish between the rc_a_* and rc_b_* pointers? 回答1: You can cast &*rc to *const T to get a pointer to the underlying data and