Rc and Arc implement 1vN ownership mechanism Observe reference count changes one example Multi-threaded powerless Rc Arc The Rust ownership mechanism requires that a value can only have one owner, which is fine in most cases, but consider the following situation: In a graph data structure, multiple edges may own the same node, and the […]
Tag: owner
Rust2 Common Programming Concepts & Understanding Ownership
Rust study notes Rust Programming Language Introduction Tutorial Course Notes Reference textbook: The Rust Programming Language (by Steve Klabnik and Carol Nichols, with contributions from the Rust Community) Lecture 3 Common Programming Concepts fn main() {<!– –> // Variables and Mutability let mut x = 5; // mut means mutable println!(“The value of x is: […]
Strings and ownership mechanisms in Rust
Article directory 1. string 2. Ownership 2.1 Ownership and Scope 2.2 Operations on ownership 2.2.1 Transfer 2.2.3 Copy 2.2.3 Delivery 2.3 Quotes 2.3.1 Borrowing 2.3.2 Mutable references 1. string I have learned that Rust only has a few basic data types, but there is no commonly used string, which is String. Today, let’s learn about […]
Smart contract ERC20 deducts the specified handling fee for each transfer to the specified address/excluding the contract owner
// SPDX-License-Identifier: MIT pragma solidity ^0.8.16; /** * @dev Interface of the ERC20 standard as defined in the EIP. */ interface IERC20 { /** * @dev Emitted when `value` tokens are moved from one account (`from`) to * another (`to`). * * Note that `value` may be zero. */ event Transfer(address indexed from, address indexed […]
[In-depth analysis of the ownership system in Rust] A Deep Dive into Rust’s Ownership System
Directory title 1. Ownership and Variable Binding 1.1 Concept of Ownership in Rust (Concept of Ownership in Rust) 1.2 How Variables Interact with Data 1.3 Transfer of Ownership 2. References and Borrowing 2.1 What is a citation? (What are References?) 2.2 Mutable vs Immutable References (Mutable vs Immutable References) 2.3 Data Races and Rust’s Borrowing […]
[2023.09.13]: Rust Lang, the inevitable ownership issue
The ownership issue of Rust was skipped when I was learning Rust because I knew it would be difficult to understand without scenarios. Unexpectedly, the scene appeared soon. When developing Yew application components, events and closures are involved, which naturally leads to ownership issues. Without further ado, let’s go directly into the code scene to […]
Create, delete users/groups. Change the group and owner of a file directory. Change the file’s permissions. Specific case. Switch users.
User information in Linux systems is stored in the /etc/passwd file Group information is generally placed in /etc/group [root@localhost home]# cat /etc/passwd root:x:0:0:root:/root:/bin/bash bin:x:1:1:bin:/bin:/sbin/nologin Use : as separator First column: username Second column: password The third column: user identifier, 0 is the identifier uid of the super user root Column 4: gid Column 5: Description […]
Rust Syntax: Ownership & References & Lifecycle
Article directory ownership Garbage collection manages memory Manual memory management Ownership of Rust ownership transfer Function ownership transfer Quoting and Borrowing Mutable and immutable references life cycle dangling reference Function life cycle declaration Structure life cycle declaration Self-inference of Rust life cycle life cycle constraints static life cycle Ownership Garbage collection management memory Languages such […]
File owner and file access permissions (8)
Directory A file attribute 1.1 Effective User ID and Effective Group ID 1.2 chown() function 1.3 Functions getuid() and getgid() Two file access permissions 2.1 General permissions 2.2 Directory permissions Three check file permissions access 3.1 access system call() 3.2 Code Test Four modify file permissions chmod 4.1 chmod function 4.2 fchmod function 4.3chmod code […]
C++ concurrent programming (5): std::unique_lock, mutex ownership transfer, lock granularity
std::unique_lockflexible locking Reference Blog Sharing data between threads – using mutexes to protect shared data C ++ multi-threaded unique_lock detailed explanation Multithreaded programming (5) – unique_lock Compared with std::lock_guard, std::unqiue_lock is not directly related to the data type of the mutex, so it is more flexible to use It can pass in additional parameters during […]