reference

问题 I have recently started working on an Android project with native calls via JNI. I've learnt about pretty restrictive limitations regarding number of references a native call can create. I would like to understand deeply how this reference management works. I studied some information but I still have a few questions that I would like to know the answers to. Without further ado: Which kinds of references in native code can cause those memory limits to be exceeded? Which count towards limits

问题 I have recently started working on an Android project with native calls via JNI. I've learnt about pretty restrictive limitations regarding number of references a native call can create. I would like to understand deeply how this reference management works. I studied some information but I still have a few questions that I would like to know the answers to. Without further ado: Which kinds of references in native code can cause those memory limits to be exceeded? Which count towards limits

问题 I'm trying to understand Rust pointer types and their relation to mutability. Specifically, the ways of declaring a variable which holds the pointer and is itself mutable -- i.e. can be pointed to some other memory, and declaring that the data itself is mutable -- i.e. can be changed through the value of the pointer variable. This is how I understand plain references work: let mut a = &5; // a is a mutable pointer to immutable data let b = &mut 5; // b is an immutable pointer to mutable data

问题 Basically the title. I see a lot of the former in the code I'm working on and I was wondering why they didn't use the latter. Are there any differences between the two? Thanks. 回答1: Straight from the documentation Unlike the Equals method and the equality operator, the ReferenceEquals method cannot be overridden. Because of this, if you want to test two object references for equality and are unsure about the implementation of the Equals method, you can call the ReferenceEquals method. However

问题 perl -E 'say for map s/(æ|ø|å)/ {qw(æ ae ø oe å aa)}->{$1}/ger, qw(rød gul blå)' perl -E 'say for map s/(æ|ø|å)/"".{qw(æ ae ø oe å aa)}->{$1}/ger, qw(rød gul blå)' The first line above gives me syntax error at -e line 1, near "}->" but the second prints roed , gul and blaa as expected. Is this a weakness of the compiler or are there some reason for it that I can't see? I tested and got this behaviour in versions 5.10, 5.22 and 5.26. 回答1: The {...} are interpreted as a BLOCK, not a hashref. We

问题 I am building a class library. This library will be deployed to the GAC. In my library, I have references to some external dependencies. The dependencies cannot be deployed to the GAC. When I deploy my library, and use it, it complains that it can't load the dependencies. How do I deploy the third-party DLLs so my assembly can reference them? 回答1: To add an assembly to the GAC, you don't need to have all the references of that assembly into the GAC as well. So as long as the application that

问题 I'm wondering if a pointer may point to a cpu register since in the case it may not, using reference instead of pointer where possible would give compiler opportunity to do some optimizations because the referenced object may reside in some register but an object pointed to by a pointer may not. 回答1: In general, CPU registers do not have memory addresses, though a CPU architecure could make them addressable (I;m not familar with any - if someone knows of one, I'd appreciate a comment).

问题 Is there any way to do this: $myVar = 2; $str = "I'm number:".$myVar; $myVar = 3; echo $str; output would be: "I'm number: 3"; I'd like to have a string where part of it would be like a pointer and its value would be set by the last modification to the referenced variable. For instance even if I do this: $myStr = "hi"; $myStrReference = &$myStr; $dynamicStr = "bye ".$myStrReference; $myStr = "bye"; echo $dynamicStr; This will output " bye hi " but I'd like it to be " bye bye " due to the last

问题 I'd implementing a simple linked list. This is the (working) code I had so far: pub struct LinkedList<T> { start: Option<Box<Link<T>>>, } impl<T> LinkedList<T> { pub fn new() -> LinkedList<T> { return LinkedList { start: None }; } } struct Link<T> { value: Box<T>, next: Option<Box<Link<T>>>, } impl<T> Link<T> { fn new_end(value: T) -> Link<T> { return Link::new(value, None); } fn new(value: T, next: Option<Box<Link<T>>>) -> Link<T> { return Link { value: Box::new(value), next, }; } } Next on

问题 I'd implementing a simple linked list. This is the (working) code I had so far: pub struct LinkedList<T> { start: Option<Box<Link<T>>>, } impl<T> LinkedList<T> { pub fn new() -> LinkedList<T> { return LinkedList { start: None }; } } struct Link<T> { value: Box<T>, next: Option<Box<Link<T>>>, } impl<T> Link<T> { fn new_end(value: T) -> Link<T> { return Link::new(value, None); } fn new(value: T, next: Option<Box<Link<T>>>) -> Link<T> { return Link { value: Box::new(value), next, }; } } Next on