重要前提
安装AI Skills的关键前提是:必须科学上网,且开启TUN模式,这一点至关重要,直接决定安装能否顺利完成,在此郑重提醒三遍:科学上网,科学上网,科学上网。查看完整安装教程 →
rust-systems-programming by manutej/luxor-claude-marketplace
npx skills add https://github.com/manutej/luxor-claude-marketplace --skill rust-systems-programming一项全面的技能,用于使用 Rust 构建高性能、内存安全的系统软件。此技能涵盖所有权、借用、并发、异步编程、不安全代码、FFI 以及面向系统级开发的性能优化。
在以下情况下使用此技能:
Rust 的所有权系统是其内存安全保证的基础:
所有权规则:
移动语义:
struct MyStruct { s: u32 }
fn main() {
let mut x = MyStruct{ s: 5u32 };
let y = x; // 所有权从 x 移动到 y
// x.s = 6; // 错误:x 不再有效
// println!("{}", x.s); // 错误:移动后无法使用 x
}
当一个类型未实现 Copy 时,赋值会移动所有权而不是复制。这在编译时防止了双重释放错误和移动后使用错误。
对于 Copy 类型:
广告位招租
在这里展示您的产品或服务
触达数万 AI 开发者,精准高效
let x = 5; // i32 实现了 Copy
let y = x; // x 被复制,而非移动
println!("{}", x); // 正常:x 仍然有效
借用允许在不取得所有权的情况下临时访问数据:
不可变借用:
fn main() {
let s1 = String::from("hello");
let len = calculate_length(&s1); // 不可变借用 s1
println!("The length of '{}' is {}.", s1, len); // s1 仍然有效
}
fn calculate_length(s: &String) -> usize {
s.len() // 可以读取但不能修改
}
可变借用:
Rust 强制执行独占可变访问以防止数据竞争:
fn main() {
let mut value = 3;
let borrow = &mut value; // 可变借用
*borrow += 1;
println!("{}", borrow); // 4
// 借用结束后,value 再次可访问
}
借用规则:
常见借用错误:
fn main() {
let mut value = 3;
// 创建 `value` 的可变借用。
let borrow = &mut value;
let _sum = value + 1; // 错误:无法使用 `value`,因为
// 它已被可变借用
println!("{}", borrow);
}
生命周期确保引用始终有效:
fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
if x.len() > y.len() {
x
} else {
y
}
}
生命周期参数 'a 告诉编译器,只要两个输入引用都有效,返回的引用就有效。
Rc(引用计数)用于单线程共享所有权:
use std::cell::RefCell;
use std::rc::Rc;
struct MyStruct { s: u32 }
fn main() {
let mut x = Rc::new(RefCell::new(MyStruct{ s: 5u32 }));
let y = x.clone(); // 增加引用计数
x.borrow_mut().s = 6; // 通过 RefCell 实现内部可变性
println!("{}", x.borrow().s);
}
Rc<T> 通过引用计数提供共享所有权。RefCell<T> 实现内部可变性,在运行时而非编译时强制执行借用规则。
Arc(原子引用计数)用于线程安全共享:
use std::sync::Arc;
use std::thread;
struct FancyNum {
num: u8,
}
fn main() {
let fancy_ref1 = Arc::new(FancyNum { num: 5 });
let fancy_ref2 = fancy_ref1.clone();
let x = thread::spawn(move || {
// `fancy_ref1` 可以被移动并具有 `'static` 生命周期
println!("child thread: {}", fancy_ref1.num);
});
x.join().expect("child thread should finish");
println!("main thread: {}", fancy_ref2.num);
}
Arc<T> 是 Rc<T> 的线程安全版本,使用原子操作进行引用计数。
Box<T>
Box<T> 是一个拥有指针,在堆上分配 T。适用于:
Rust 通过其所有权系统在编译时防止数据竞争:
use std::thread;
use std::sync::mpsc;
fn main() {
let (tx, rx) = mpsc::channel();
thread::spawn(move || {
tx.send("Hello from thread").unwrap();
});
let message = rx.recv().unwrap();
println!("{}", message);
}
use std::sync::{Arc, Mutex};
use std::thread;
fn main() {
let counter = Arc::new(Mutex::new(0));
let mut handles = vec![];
for _ in 0..10 {
let counter = Arc::clone(&counter);
let handle = thread::spawn(move || {
let mut num = counter.lock().unwrap();
*num += 1;
});
handles.push(handle);
}
for handle in handles {
handle.join().unwrap();
}
println!("Result: {}", *counter.lock().unwrap());
}
关键并发类型:
Mutex<T>:用于共享可变状态的互斥锁RwLock<T>:允许多个读者或一个写者的读写锁Arc<T>:用于线程安全共享的原子引用计数mpsc:多生产者、单消费者通道ThreadSanitizer 示例:
static mut A: usize = 0;
fn main() {
let t = std::thread::spawn(|| {
unsafe { A += 1 };
});
unsafe { A += 1 };
t.join().unwrap();
}
此代码存在数据竞争。ThreadSanitizer(通过 RUSTFLAGS=-Zsanitizer=thread 启用)检测到对静态可变数据的并发访问:
WARNING: ThreadSanitizer: data race (pid=10574)
Read of size 8 at 0x5632dfe3d030 by thread T1:
Previous write of size 8 at 0x5632dfe3d030 by main thread:
Rust 中的异步编程允许在不阻塞线程的情况下进行并发 I/O:
async fn foo(n: usize) {
if n > 0 {
Box::pin(foo(n - 1)).await;
}
}
递归异步函数需要 Box::pin() 来为 future 提供已知大小。
具有移动语义的异步闭包:
fn force_fnonce<T: async FnOnce()>(t: T) -> T { t }
let x = String::new();
let c = force_fnonce(async move || {
println!("{x}");
});
当约束为 AsyncFnOnce 时,闭包通过移动捕获以确保正确的所有权。
异步闭包借用:
let x = &1i32; // 生命周期 '1
let c = async move || {
println!("{:?}", *x);
// 即使闭包移动了 x,我们只捕获 *x,
// 因此内部协程可以以其原始生命周期重新借用数据。
};
异步闭包中的可变借用:
let mut x = 1i32;
let c = async || {
x = 1;
// 父作用域可变借用 `x`。
// 当我们调用 `c()` 时,我们隐式地为 `AsyncFnMut::async_call_mut` 进行自动引用。
// 内部协程以协程-闭包的生命周期进行捕获。
};
E0373: 异步块捕获短生命周期变量:
use std::future::Future;
async fn f() {
let v = vec![1, 2, 3i32];
spawn(async { //~ ERROR E0373
println!("{:?}", v) // v 可能在异步块运行前离开作用域
});
}
fn spawn<F: Future + Send + 'static>(future: F) {
unimplemented!()
}
解决方案:将变量移动到异步块中:
spawn(async move {
println!("{:?}", v)
})
Rust 的 unsafe 关键字允许编译器无法验证的操作:
不安全解引用示例:
macro_rules! unsafe_deref {
() => {
*(&() as *const ())
};
}
不安全 Sync 实现:
use std::cell::Cell;
struct NotThreadSafe<T> {
value: Cell<T>,
}
unsafe impl<T> Sync for NotThreadSafe<T> {}
static A: NotThreadSafe<usize> = NotThreadSafe { value : Cell::new(1) };
static B: &'static NotThreadSafe<usize> = &A; // 正常!
这是 unsafe 的,因为您必须手动确保线程安全。默认情况下 Cell 不是 Sync,因此此实现需要仔细推理。
从 Rust 调用 C 函数:
use std::mem;
#[link(name = "foo")]
extern "C" {
fn do_twice(f: unsafe extern "C" fn(i32) -> i32, arg: i32) -> i32;
}
unsafe extern "C" fn add_one(x: i32) -> i32 {
x + 1
}
unsafe extern "C" fn add_two(x: i64) -> i64 {
x + 2
}
fn main() {
let answer = unsafe { do_twice(add_one, 5) };
println!("The answer is: {}", answer);
// 类型不匹配的调用(不安全):
println!("With CFI enabled, you should not see the next answer");
let f: unsafe extern "C" fn(i32) -> i32 = unsafe {
mem::transmute::<*const u8, unsafe extern "C" fn(i32) -> i32>(add_two as *const u8)
};
let next_answer = unsafe { do_twice(f, 5) };
println!("The next answer is: {}", next_answer);
}
控制流完整性(CFI): 启用 CFI 后,类型不匹配的转换会导致程序终止,从而防止控制流劫持。
用于系统调用的内联汇编:
static UNMAP_BASE: usize;
const MEM_RELEASE: usize;
static VirtualFree: usize;
const OffPtr: usize;
const OffFn: usize;
core::arch::asm!("
push {free_type}
push {free_size}
push {base}
mov eax, fs:[30h]
mov eax, [eax+8h]
add eax, {off_fn}
mov [eax-{off_fn}+{off_ptr}], eax
push eax
jmp {virtual_free}
",
off_ptr = const OffPtr,
off_fn = const OffFn,
free_size = const 0,
free_type = const MEM_RELEASE,
virtual_free = sym VirtualFree,
base = sym UNMAP_BASE,
options(noreturn),
);
此示例演示了使用内联汇编进行 Windows 内存释放的直接系统调用。
Rust 使用 Result<T, E> 和 Option<T> 进行错误处理:
fn divide(a: i32, b: i32) -> Result<i32, String> {
if b == 0 {
Err("Division by zero".to_string())
} else {
Ok(a / b)
}
}
fn main() {
match divide(10, 2) {
Ok(result) => println!("Result: {}", result),
Err(e) => println!("Error: {}", e),
}
}
fn process_file(path: &str) -> Result<String, std::io::Error> {
let content = std::fs::read_to_string(path)?;
Ok(content.to_uppercase())
}
? 运算符将错误传播到调用栈上层,类似于异常,但在类型签名中是显式的。
use std::fmt;
#[derive(Debug)]
enum AppError {
IoError(std::io::Error),
ParseError(std::num::ParseIntError),
Custom(String),
}
impl fmt::Display for AppError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
AppError::IoError(e) => write!(f, "IO error: {}", e),
AppError::ParseError(e) => write!(f, "Parse error: {}", e),
AppError::Custom(msg) => write!(f, "Error: {}", msg),
}
}
}
impl std::error::Error for AppError {}
检测栈缓冲区溢出:
fn main() {
let xs = [0, 1, 2, 3];
let _y = unsafe { *xs.as_ptr().offset(4) };
}
使用 AddressSanitizer 构建:
$ export RUSTFLAGS=-Zsanitizer=address RUSTDOCFLAGS=-Zsanitizer=address
$ cargo run -Zbuild-std --target x86_64-unknown-linux-gnu
输出:
==37882==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffe400e6250
READ of size 4 at 0x7ffe400e6250 thread T0
#0 0x5609a841fb1f in example::main::h628ffc6626ed85b2 /.../src/main.rs:3:23
Address 0x7ffe400e6250 is located in stack of thread T0 at offset 48 in frame
This frame has 1 object(s):
[32, 48) 'xs' (line 2) <== Memory access at offset 48 overflows this variable
检测堆缓冲区溢出:
fn main() {
let xs = vec![0, 1, 2, 3];
let _y = unsafe { *xs.as_ptr().offset(4) };
}
检测作用域后使用:
static mut P: *mut usize = std::ptr::null_mut();
fn main() {
unsafe {
{
let mut x = 0;
P = &mut x;
}
std::ptr::write_volatile(P, 123); // P 指向已丢弃的变量
}
}
AddressSanitizer 输出:
==39249==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7ffc7ed3e1a0
WRITE of size 8 at 0x7ffc7ed3e1a0 thread T0
Rust 提供高级抽象而无需运行时开销:
// 迭代器链被优化为简单循环
let sum: i32 = (1..100)
.filter(|x| x % 2 == 0)
.map(|x| x * x)
.sum();
编译器将此优化为等同于手动迭代的紧凑循环。
泛型函数针对每种具体类型进行单态化(特化):
#[inline]
fn add<T: std::ops::Add<Output = T>>(a: T, b: T) -> T {
a + b
}
let x = add(5, 3); // 针对 i32 特化
let y = add(5.0, 3.0); // 针对 f64 特化
不同的智能指针具有不同的开销:
Box<T>:单次堆分配,无开销Rc<T>:引用计数,每次克隆/丢弃有少量开销Arc<T>:原子引用计数,为线程安全有更高开销Mutex<T>:锁获取开销RefCell<T>:运行时借用检查开销// 不好:分配新的 String
fn greet_bad(name: &str) -> String {
format!("Hello, {}", name)
}
// 好:返回引用,无分配
fn greet_good(name: &str) -> impl std::fmt::Display + '_ {
format_args!("Hello, {}", name)
}
struct Config {
host: String,
port: u16,
timeout: u64,
}
impl Config {
fn builder() -> ConfigBuilder {
ConfigBuilder::default()
}
}
#[derive(Default)]
struct ConfigBuilder {
host: Option<String>,
port: Option<u16>,
timeout: Option<u64>,
}
impl ConfigBuilder {
fn host(mut self, host: impl Into<String>) -> Self {
self.host = Some(host.into());
self
}
fn port(mut self, port: u16) -> Self {
self.port = Some(port);
self
}
fn build(self) -> Config {
Config {
host: self.host.unwrap_or_else(|| "localhost".to_string()),
port: self.port.unwrap_or(8080),
timeout: self.timeout.unwrap_or(30),
}
}
}
struct UserId(u64);
struct PostId(u64);
fn get_user(id: UserId) -> User { /* ... */ }
// 这不会编译:类型安全!
// get_user(PostId(42));
struct FileGuard {
file: std::fs::File,
}
impl FileGuard {
fn new(path: &str) -> std::io::Result<Self> {
Ok(FileGuard {
file: std::fs::File::create(path)?,
})
}
}
impl Drop for FileGuard {
fn drop(&mut self) {
println!("File closed automatically");
}
}
问题:
fn you_know_nothing(jon_snow: &mut i32) {
let nights_watch = &jon_snow;
let starks = || {
*jon_snow = 3; // 错误:闭包需要独占访问 `jon_snow`
// 但它已被借用
};
println!("{}", nights_watch);
}
解决方案:
fn you_know_nothing(jon_snow: &mut i32) {
let nights_watch = &jon_snow;
println!("{}", nights_watch); // 先使用借用
// 借用在此结束(非词法生命周期)
let starks = || {
*jon_snow = 3; // 现在正常
};
}
问题:
fn bar(x: &mut i32) {}
fn foo(a: &mut i32) {
let y = &a;
bar(a); // 错误:在不可变借用时无法可变借用
println!("{}", y);
}
解决方案:
fn bar(x: &mut i32) {}
fn foo(a: &mut i32) {
bar(a); // 先进行可变借用
let y = &a; // 可变借用结束后进行不可变借用
println!("{}", y);
}
问题:
struct Value {}
fn borrow(val: &Value) {}
fn eat(val: Value) {}
fn main() {
let x = Value{};
let _ref_to_val: &Value = &x;
eat(x); // 错误:借用时无法移动 x
borrow(_ref_to_val);
}
问题:
fn set(x: &mut isize) {
*x += 4;
}
fn dragoooon(x: &mut isize) {
let mut c1 = || set(x);
let mut c2 = || set(x); // 错误:两个闭包尝试可变借用
c2();
c1();
}
解决方案 1: 顺序执行(非词法生命周期)
fn set(x: &mut isize) {
*x += 4;
}
fn dragoooon(x: &mut isize) {
{
let mut c1 = || set(&mut *x);
c1();
} // `c1` 在此已被丢弃,因此我们可以再次自由使用 `x`!
let mut c2 = || set(&mut *x);
c2();
}
解决方案 2: 使用 Rc + RefCell 实现共享可变访问
use std::rc::Rc;
use std::cell::RefCell;
fn set(x: &mut isize) {
*x += 4;
}
fn dragoooon(x: &mut isize) {
let x = Rc::new(RefCell::new(x));
let y = Rc::clone(&x);
let mut c1 = || { let mut x2 = x.borrow_mut(); set(&mut x2); };
let mut c2 = || { let mut x2 = y.borrow_mut(); set(&mut x2); };
c2();
c1();
}
问题:
use std::cell::RefCell;
struct TheDarkKnight;
impl TheDarkKnight {
fn nothing_is_true(self) {}
}
fn main() {
let x = RefCell::new(TheDarkKnight);
x.borrow().nothing_is_true(); // 错误:无法移出借用内容
}
解决方案 1: 获取引用
impl TheDarkKnight {
fn nothing_is_true(&self) {} // 改为 &self
}
fn main() {
let x = RefCell::new(TheDarkKnight);
x.borrow().nothing_is_true(); // 正常
}
解决方案 2: 重新获取所有权
fn main() {
let x = RefCell::new(TheDarkKnight);
let x = x.into_inner(); // 重新获取所有权
x.nothing_is_true(); // 正常
}
use tracing::{info, warn, error, instrument};
#[instrument]
async fn process_request(id: u64) -> Result<(), Error> {
info!(request_id = id, "Processing request");
match do_work(id).await {
Ok(_) => {
info!("Request completed successfully");
Ok(())
}
Err(e) => {
error!(error = ?e, "Request failed");
Err(e)
}
}
}
use serde::Deserialize;
#[derive(Deserialize)]
struct AppConfig {
database_url: String,
server_port: u16,
log_level: String,
}
fn load_config() -> Result<AppConfig, config::ConfigError> {
config::Config::builder()
.add_source(config::File::with_name("config"))
.add_source(config::Environment::with_prefix("APP"))
.build()?
.try_deserialize()
}
use tokio::signal;
async fn shutdown_signal() {
let ctrl_c = async {
signal::ctrl_c()
.await
.expect("failed to install Ctrl+C handler");
};
#[cfg(unix)]
let terminate = async {
signal::unix::signal(signal::unix::SignalKind::terminate())
.expect("failed to install signal handler")
.recv()
.await;
};
#[cfg(not(unix))]
let terminate = std::future::pending::<()>();
tokio::select! {
_ = ctrl_c => {},
_ = terminate => {},
}
println!("Shutdown signal received, starting graceful shutdown");
}
use deadpool_postgres::{Config, Pool, Runtime};
use tokio_postgres::NoTls;
async fn create_pool() -> Pool {
let mut cfg = Config::new();
cfg.host = Some("localhost".to_string());
cfg.dbname = Some("mydb".to_string());
cfg.create_pool(Some(Runtime::Tokio1), NoTls)
.expect("Failed to create pool")
}
async fn query_user(pool: &Pool, id: i64) -> Result<User, Error> {
let client = pool.get().await?;
let row = client
.query_one("SELECT * FROM users WHERE id = $1", &[&id])
.await?;
Ok(User::from_row(row))
}
&T 而非 TString 而非 &strDebug、Clone、PartialEq、Send、SyncInto<T> 提高灵活性:fn set_name(&mut self, name: impl Into<String>)#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_addition() {
assert_eq!(add(2, 2), 4);
}
#[test]
#[should_panic(expected = "division by zero")]
fn test_divide_by_zero() {
divide(10, 0);
}
#[tokio::test]
async fn test_async_function() {
let result = fetch_data().await;
assert!(result.is_ok());
}
}
/// 计算两个数字的和。
///
/// # 示例
///
/// ```
/// let result = add(2, 2);
/// assert_eq!(result, 4);
/// ```
///
/// # Panics
///
/// 如果结果溢出,此函数将会 panic。
pub fn add(a: i32, b: i32) -> i32 {
a.checked_add(b).expect("overflow in add")
}
[dependencies]
tokio = { version = "1", features = ["full"] }
serde = { version = "1", features = ["derive"] }
tracing = "0.1"
[dev-dependencies]
criterion = "0.5"
[profile.release]
lto = true
codegen-units = 1
问题:"无法可变借用,因为它也被不可变借用" 解决方案:确保可变借用和不可变借用作用域不重叠
问题:"无法移出借用内容"
解决方案:克隆值、获取引用或使用 Rc<RefCell<T>>
问题:"引用生命周期问题" 解决方案:添加显式生命周期注解或重构代码以避免复杂生命周期
问题:编译时间慢
解决方案:使用增量编译,减少泛型实例化,使用 cargo check
问题:运行时性能低于预期
解决方案:使用 perf 进行性能分析,启用 LTO,检查不必要的分配/克隆
问题:内存使用率高 解决方案:使用引用而非克隆,考虑流式处理数据,使用 Valgrind 进行性能分析
问题:多个互斥锁导致死锁
解决方案:始终以相同顺序获取锁,使用带超时的 try_lock
问题:不安全代码中的数据竞争 解决方案:使用 ThreadSanitizer 运行,仔细检查不安全代码块
问题:异步任务无进展
解决方案:检查异步代码中的阻塞操作,对 CPU 密集型工作使用 spawn_blocking
Box<T> - 堆分配,单一所有者
Rc<T> - 引用计数,单线程
Arc<T> - 原子引用计数,线程安全
Mutex<T> - 互斥锁
RwLock<T> - 读写锁
RefCell<T> - 运行时借用检查
Cell<T> - 用于 Copy 类型的内部可变性
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
struct MyStruct {
field: String,
}
impl Default for MyStruct {
fn default() -> Self {
Self {
field: String::new(),
}
}
}
impl std::fmt::Display for MyStruct {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
write!(f, "MyStruct({})", self.field)
}
}
Tokio: 功能齐全,最受欢迎,生态系统优秀
async-std: 镜像标准库 API,对初学者更简单
smol: 轻量级,依赖最少
技能版本 : 1.0.0 最后更新 : 2025年10月 技能类别 : 系统编程、性能、内存安全 Context7 集成 : Rust 文档和错误代码示例
每周安装
63
仓库
GitHub 星标
47
首次出现
2026年1月22日
安全审计
安装于
gemini-cli47
cursor47
opencode47
codex44
claude-code42
github-copilot41
A comprehensive skill for building high-performance, memory-safe systems software using Rust. This skill covers ownership, borrowing, concurrency, async programming, unsafe code, FFI, and performance optimization for systems-level development.
Use this skill when:
Rust's ownership system is the foundation of its memory safety guarantees:
Ownership Rules:
Move Semantics:
struct MyStruct { s: u32 }
fn main() {
let mut x = MyStruct{ s: 5u32 };
let y = x; // Ownership moved from x to y
// x.s = 6; // ERROR: x is no longer valid
// println!("{}", x.s); // ERROR: cannot use x after move
}
When a type doesn't implement Copy, assignment moves ownership rather than copying. This prevents double-free errors and use-after-move bugs at compile time.
For Copy Types:
let x = 5; // i32 implements Copy
let y = x; // x is copied, not moved
println!("{}", x); // OK: x is still valid
Borrowing allows temporary access to data without taking ownership:
Immutable Borrowing:
fn main() {
let s1 = String::from("hello");
let len = calculate_length(&s1); // Borrow s1 immutably
println!("The length of '{}' is {}.", s1, len); // s1 still valid
}
fn calculate_length(s: &String) -> usize {
s.len() // Can read but not modify
}
Mutable Borrowing:
Rust enforces exclusive mutable access to prevent data races:
fn main() {
let mut value = 3;
let borrow = &mut value; // Mutable borrow
*borrow += 1;
println!("{}", borrow); // 4
// value is accessible again after borrow ends
}
Borrowing Rules:
Common Borrowing Error:
fn main() {
let mut value = 3;
// Create a mutable borrow of `value`.
let borrow = &mut value;
let _sum = value + 1; // ERROR: cannot use `value` because
// it was mutably borrowed
println!("{}", borrow);
}
Lifetimes ensure references are always valid:
fn longest<'a>(x: &'a str, y: &'a str) -> &'a str {
if x.len() > y.len() {
x
} else {
y
}
}
The 'a lifetime parameter tells the compiler that the returned reference will be valid as long as both input references are valid.
Rc (Reference Counted) for Single-threaded Shared Ownership:
use std::cell::RefCell;
use std::rc::Rc;
struct MyStruct { s: u32 }
fn main() {
let mut x = Rc::new(RefCell::new(MyStruct{ s: 5u32 }));
let y = x.clone(); // Increment reference count
x.borrow_mut().s = 6; // Interior mutability via RefCell
println!("{}", x.borrow().s);
}
Rc<T> provides shared ownership with reference counting. RefCell<T> enables interior mutability, enforcing borrow rules at runtime rather than compile time.
Arc (Atomic Reference Counted) for Thread-safe Sharing:
use std::sync::Arc;
use std::thread;
struct FancyNum {
num: u8,
}
fn main() {
let fancy_ref1 = Arc::new(FancyNum { num: 5 });
let fancy_ref2 = fancy_ref1.clone();
let x = thread::spawn(move || {
// `fancy_ref1` can be moved and has a `'static` lifetime
println!("child thread: {}", fancy_ref1.num);
});
x.join().expect("child thread should finish");
println!("main thread: {}", fancy_ref2.num);
}
Arc<T> is the thread-safe version of Rc<T>, using atomic operations for reference counting.
Box<T>
Box<T> is an owning pointer that allocates T on the heap. Useful for:
Rust prevents data races at compile time through its ownership system:
use std::thread;
use std::sync::mpsc;
fn main() {
let (tx, rx) = mpsc::channel();
thread::spawn(move || {
tx.send("Hello from thread").unwrap();
});
let message = rx.recv().unwrap();
println!("{}", message);
}
use std::sync::{Arc, Mutex};
use std::thread;
fn main() {
let counter = Arc::new(Mutex::new(0));
let mut handles = vec![];
for _ in 0..10 {
let counter = Arc::clone(&counter);
let handle = thread::spawn(move || {
let mut num = counter.lock().unwrap();
*num += 1;
});
handles.push(handle);
}
for handle in handles {
handle.join().unwrap();
}
println!("Result: {}", *counter.lock().unwrap());
}
Key Concurrency Types:
Mutex<T>: Mutual exclusion lock for shared mutable stateRwLock<T>: Reader-writer lock allowing multiple readers or one writerArc<T>: Atomic reference counting for thread-safe sharingmpsc: Multi-producer, single-consumer channelsThreadSanitizer Example:
static mut A: usize = 0;
fn main() {
let t = std::thread::spawn(|| {
unsafe { A += 1 };
});
unsafe { A += 1 };
t.join().unwrap();
}
This code has a data race. ThreadSanitizer (enabled with RUSTFLAGS=-Zsanitizer=thread) detects concurrent access to static mutable data:
WARNING: ThreadSanitizer: data race (pid=10574)
Read of size 8 at 0x5632dfe3d030 by thread T1:
Previous write of size 8 at 0x5632dfe3d030 by main thread:
Async programming in Rust allows concurrent I/O without blocking threads:
async fn foo(n: usize) {
if n > 0 {
Box::pin(foo(n - 1)).await;
}
}
Recursive async functions require Box::pin() to give the future a known size.
Async Closure with Move Semantics:
fn force_fnonce<T: async FnOnce()>(t: T) -> T { t }
let x = String::new();
let c = force_fnonce(async move || {
println!("{x}");
});
When constrained to AsyncFnOnce, the closure captures by move to ensure proper ownership.
Async Closure Borrowing:
let x = &1i32; // Lifetime '1
let c = async move || {
println!("{:?}", *x);
// Even though the closure moves x, we're only capturing *x,
// so the inner coroutine can reborrow the data for its original lifetime.
};
Mutable Borrowing in Async Closures:
let mut x = 1i32;
let c = async || {
x = 1;
// The parent borrows `x` mutably.
// When we call `c()`, we implicitly autoref for `AsyncFnMut::async_call_mut`.
// The inner coroutine captures with the lifetime of the coroutine-closure.
};
E0373: Async block capturing short-lived variable:
use std::future::Future;
async fn f() {
let v = vec![1, 2, 3i32];
spawn(async { //~ ERROR E0373
println!("{:?}", v) // v might go out of scope before async block runs
});
}
fn spawn<F: Future + Send + 'static>(future: F) {
unimplemented!()
}
Solution: Move the variable into the async block:
spawn(async move {
println!("{:?}", v)
})
Rust's unsafe keyword allows operations that the compiler cannot verify:
Unsafe Dereference Example:
macro_rules! unsafe_deref {
() => {
*(&() as *const ())
};
}
Unsafe Sync Implementation:
use std::cell::Cell;
struct NotThreadSafe<T> {
value: Cell<T>,
}
unsafe impl<T> Sync for NotThreadSafe<T> {}
static A: NotThreadSafe<usize> = NotThreadSafe { value : Cell::new(1) };
static B: &'static NotThreadSafe<usize> = &A; // ok!
This is unsafe because you must manually ensure thread safety. Cell is not Sync by default, so this implementation requires careful reasoning.
Calling C Functions from Rust:
use std::mem;
#[link(name = "foo")]
extern "C" {
fn do_twice(f: unsafe extern "C" fn(i32) -> i32, arg: i32) -> i32;
}
unsafe extern "C" fn add_one(x: i32) -> i32 {
x + 1
}
unsafe extern "C" fn add_two(x: i64) -> i64 {
x + 2
}
fn main() {
let answer = unsafe { do_twice(add_one, 5) };
println!("The answer is: {}", answer);
// Type-mismatched call (unsafe):
println!("With CFI enabled, you should not see the next answer");
let f: unsafe extern "C" fn(i32) -> i32 = unsafe {
mem::transmute::<*const u8, unsafe extern "C" fn(i32) -> i32>(add_two as *const u8)
};
let next_answer = unsafe { do_twice(f, 5) };
println!("The next answer is: {}", next_answer);
}
Control Flow Integrity (CFI): With CFI enabled, the type-mismatched transmute causes program termination, preventing control flow hijacking.
Inline Assembly for System Calls:
static UNMAP_BASE: usize;
const MEM_RELEASE: usize;
static VirtualFree: usize;
const OffPtr: usize;
const OffFn: usize;
core::arch::asm!("
push {free_type}
push {free_size}
push {base}
mov eax, fs:[30h]
mov eax, [eax+8h]
add eax, {off_fn}
mov [eax-{off_fn}+{off_ptr}], eax
push eax
jmp {virtual_free}
",
off_ptr = const OffPtr,
off_fn = const OffFn,
free_size = const 0,
free_type = const MEM_RELEASE,
virtual_free = sym VirtualFree,
base = sym UNMAP_BASE,
options(noreturn),
);
This demonstrates direct system calls using inline assembly for Windows memory deallocation.
Rust uses Result<T, E> and Option<T> for error handling:
fn divide(a: i32, b: i32) -> Result<i32, String> {
if b == 0 {
Err("Division by zero".to_string())
} else {
Ok(a / b)
}
}
fn main() {
match divide(10, 2) {
Ok(result) => println!("Result: {}", result),
Err(e) => println!("Error: {}", e),
}
}
fn process_file(path: &str) -> Result<String, std::io::Error> {
let content = std::fs::read_to_string(path)?;
Ok(content.to_uppercase())
}
The ? operator propagates errors up the call stack, similar to exceptions but explicit in the type signature.
use std::fmt;
#[derive(Debug)]
enum AppError {
IoError(std::io::Error),
ParseError(std::num::ParseIntError),
Custom(String),
}
impl fmt::Display for AppError {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
AppError::IoError(e) => write!(f, "IO error: {}", e),
AppError::ParseError(e) => write!(f, "Parse error: {}", e),
AppError::Custom(msg) => write!(f, "Error: {}", msg),
}
}
}
impl std::error::Error for AppError {}
Detecting Stack Buffer Overflow:
fn main() {
let xs = [0, 1, 2, 3];
let _y = unsafe { *xs.as_ptr().offset(4) };
}
Build with AddressSanitizer:
$ export RUSTFLAGS=-Zsanitizer=address RUSTDOCFLAGS=-Zsanitizer=address
$ cargo run -Zbuild-std --target x86_64-unknown-linux-gnu
Output:
==37882==ERROR: AddressSanitizer: stack-buffer-overflow on address 0x7ffe400e6250
READ of size 4 at 0x7ffe400e6250 thread T0
#0 0x5609a841fb1f in example::main::h628ffc6626ed85b2 /.../src/main.rs:3:23
Address 0x7ffe400e6250 is located in stack of thread T0 at offset 48 in frame
This frame has 1 object(s):
[32, 48) 'xs' (line 2) <== Memory access at offset 48 overflows this variable
Detecting Heap Buffer Overflow:
fn main() {
let xs = vec![0, 1, 2, 3];
let _y = unsafe { *xs.as_ptr().offset(4) };
}
Detecting Use-After-Scope:
static mut P: *mut usize = std::ptr::null_mut();
fn main() {
unsafe {
{
let mut x = 0;
P = &mut x;
}
std::ptr::write_volatile(P, 123); // P points to dropped variable
}
}
AddressSanitizer output:
==39249==ERROR: AddressSanitizer: stack-use-after-scope on address 0x7ffc7ed3e1a0
WRITE of size 8 at 0x7ffc7ed3e1a0 thread T0
Rust provides high-level abstractions without runtime overhead:
// Iterator chains are optimized to simple loops
let sum: i32 = (1..100)
.filter(|x| x % 2 == 0)
.map(|x| x * x)
.sum();
The compiler optimizes this to a tight loop equivalent to manual iteration.
Generic functions are monomorphized (specialized) for each concrete type:
#[inline]
fn add<T: std::ops::Add<Output = T>>(a: T, b: T) -> T {
a + b
}
let x = add(5, 3); // Specialized for i32
let y = add(5.0, 3.0); // Specialized for f64
Different smart pointers have different costs:
Box<T>: Single heap allocation, no overheadRc<T>: Reference counting, small overhead per clone/dropArc<T>: Atomic reference counting, higher overhead for thread safetyMutex<T>: Lock acquisition overheadRefCell<T>: Runtime borrow checking overhead// Bad: Allocates a new String
fn greet_bad(name: &str) -> String {
format!("Hello, {}", name)
}
// Good: Returns a reference, no allocation
fn greet_good(name: &str) -> impl std::fmt::Display + '_ {
format_args!("Hello, {}", name)
}
struct Config {
host: String,
port: u16,
timeout: u64,
}
impl Config {
fn builder() -> ConfigBuilder {
ConfigBuilder::default()
}
}
#[derive(Default)]
struct ConfigBuilder {
host: Option<String>,
port: Option<u16>,
timeout: Option<u64>,
}
impl ConfigBuilder {
fn host(mut self, host: impl Into<String>) -> Self {
self.host = Some(host.into());
self
}
fn port(mut self, port: u16) -> Self {
self.port = Some(port);
self
}
fn build(self) -> Config {
Config {
host: self.host.unwrap_or_else(|| "localhost".to_string()),
port: self.port.unwrap_or(8080),
timeout: self.timeout.unwrap_or(30),
}
}
}
struct UserId(u64);
struct PostId(u64);
fn get_user(id: UserId) -> User { /* ... */ }
// This won't compile: type safety!
// get_user(PostId(42));
struct FileGuard {
file: std::fs::File,
}
impl FileGuard {
fn new(path: &str) -> std::io::Result<Self> {
Ok(FileGuard {
file: std::fs::File::create(path)?,
})
}
}
impl Drop for FileGuard {
fn drop(&mut self) {
println!("File closed automatically");
}
}
Problem:
fn you_know_nothing(jon_snow: &mut i32) {
let nights_watch = &jon_snow;
let starks = || {
*jon_snow = 3; // error: closure requires unique access to `jon_snow`
// but it is already borrowed
};
println!("{}", nights_watch);
}
Solution:
fn you_know_nothing(jon_snow: &mut i32) {
let nights_watch = &jon_snow;
println!("{}", nights_watch); // Use the borrow first
// Borrow ends here (non-lexical lifetimes)
let starks = || {
*jon_snow = 3; // Now OK
};
}
Problem:
fn bar(x: &mut i32) {}
fn foo(a: &mut i32) {
let y = &a;
bar(a); // Error: cannot borrow as mutable while borrowed as immutable
println!("{}", y);
}
Solution:
fn bar(x: &mut i32) {}
fn foo(a: &mut i32) {
bar(a); // Mutable borrow first
let y = &a; // Immutable borrow after mutable borrow ends
println!("{}", y);
}
Problem:
struct Value {}
fn borrow(val: &Value) {}
fn eat(val: Value) {}
fn main() {
let x = Value{};
let _ref_to_val: &Value = &x;
eat(x); // Error: cannot move x while borrowed
borrow(_ref_to_val);
}
Problem:
fn set(x: &mut isize) {
*x += 4;
}
fn dragoooon(x: &mut isize) {
let mut c1 = || set(x);
let mut c2 = || set(x); // error: two closures trying to borrow mutably
c2();
c1();
}
Solution 1: Sequential Execution (Non-Lexical Lifetimes)
fn set(x: &mut isize) {
*x += 4;
}
fn dragoooon(x: &mut isize) {
{
let mut c1 = || set(&mut *x);
c1();
} // `c1` has been dropped here so we're free to use `x` again!
let mut c2 = || set(&mut *x);
c2();
}
Solution 2: Rc + RefCell for Shared Mutable Access
use std::rc::Rc;
use std::cell::RefCell;
fn set(x: &mut isize) {
*x += 4;
}
fn dragoooon(x: &mut isize) {
let x = Rc::new(RefCell::new(x));
let y = Rc::clone(&x);
let mut c1 = || { let mut x2 = x.borrow_mut(); set(&mut x2); };
let mut c2 = || { let mut x2 = y.borrow_mut(); set(&mut x2); };
c2();
c1();
}
Problem:
use std::cell::RefCell;
struct TheDarkKnight;
impl TheDarkKnight {
fn nothing_is_true(self) {}
}
fn main() {
let x = RefCell::new(TheDarkKnight);
x.borrow().nothing_is_true(); // Error: cannot move out of borrowed content
}
Solution 1: Take a Reference
impl TheDarkKnight {
fn nothing_is_true(&self) {} // Change to &self
}
fn main() {
let x = RefCell::new(TheDarkKnight);
x.borrow().nothing_is_true(); // OK
}
Solution 2: Reclaim Ownership
fn main() {
let x = RefCell::new(TheDarkKnight);
let x = x.into_inner(); // Reclaim ownership
x.nothing_is_true(); // OK
}
use tracing::{info, warn, error, instrument};
#[instrument]
async fn process_request(id: u64) -> Result<(), Error> {
info!(request_id = id, "Processing request");
match do_work(id).await {
Ok(_) => {
info!("Request completed successfully");
Ok(())
}
Err(e) => {
error!(error = ?e, "Request failed");
Err(e)
}
}
}
use serde::Deserialize;
#[derive(Deserialize)]
struct AppConfig {
database_url: String,
server_port: u16,
log_level: String,
}
fn load_config() -> Result<AppConfig, config::ConfigError> {
config::Config::builder()
.add_source(config::File::with_name("config"))
.add_source(config::Environment::with_prefix("APP"))
.build()?
.try_deserialize()
}
use tokio::signal;
async fn shutdown_signal() {
let ctrl_c = async {
signal::ctrl_c()
.await
.expect("failed to install Ctrl+C handler");
};
#[cfg(unix)]
let terminate = async {
signal::unix::signal(signal::unix::SignalKind::terminate())
.expect("failed to install signal handler")
.recv()
.await;
};
#[cfg(not(unix))]
let terminate = std::future::pending::<()>();
tokio::select! {
_ = ctrl_c => {},
_ = terminate => {},
}
println!("Shutdown signal received, starting graceful shutdown");
}
use deadpool_postgres::{Config, Pool, Runtime};
use tokio_postgres::NoTls;
async fn create_pool() -> Pool {
let mut cfg = Config::new();
cfg.host = Some("localhost".to_string());
cfg.dbname = Some("mydb".to_string());
cfg.create_pool(Some(Runtime::Tokio1), NoTls)
.expect("Failed to create pool")
}
async fn query_user(pool: &Pool, id: i64) -> Result<User, Error> {
let client = pool.get().await?;
let row = client
.query_one("SELECT * FROM users WHERE id = $1", &[&id])
.await?;
Ok(User::from_row(row))
}
&T instead of T unless you need ownershipString instead of &str for simpler APIsDebug, Clone, PartialEq, Send, SyncInto<T> for Flexibility: #[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_addition() {
assert_eq!(add(2, 2), 4);
}
#[test]
#[should_panic(expected = "division by zero")]
fn test_divide_by_zero() {
divide(10, 0);
}
#[tokio::test]
async fn test_async_function() {
let result = fetch_data().await;
assert!(result.is_ok());
}
}
/// Calculates the sum of two numbers.
///
/// # Examples
///
/// ```
/// let result = add(2, 2);
/// assert_eq!(result, 4);
/// ```
///
/// # Panics
///
/// This function will panic if the result overflows.
pub fn add(a: i32, b: i32) -> i32 {
a.checked_add(b).expect("overflow in add")
}
[dependencies]
tokio = { version = "1", features = ["full"] }
serde = { version = "1", features = ["derive"] }
tracing = "0.1"
[dev-dependencies]
criterion = "0.5"
[profile.release]
lto = true
codegen-units = 1
Issue : "Cannot borrow as mutable because it is also borrowed as immutable" Solution : Ensure mutable and immutable borrows don't overlap in scope
Issue : "Cannot move out of borrowed content" Solution : Clone the value, take a reference, or use Rc<RefCell<T>>
Issue : "Lifetime issues with references" Solution : Add explicit lifetime annotations or restructure code to avoid complex lifetimes
Issue : Slow compilation times Solution : Use incremental compilation, reduce generic instantiations, use cargo check
Issue : Runtime performance slower than expected Solution : Profile with perf, enable LTO, check for unnecessary allocations/clones
Issue : High memory usage Solution : Use references instead of clones, consider streaming data, profile with Valgrind
Issue : Deadlocks with multiple mutexes Solution : Always acquire locks in the same order, use try_lock with timeout
Issue : Data races in unsafe code Solution : Run with ThreadSanitizer, carefully review unsafe blocks
Issue : Async tasks not making progress Solution : Check for blocking operations in async code, use spawn_blocking for CPU-bound work
Box<T> - Heap allocation, single owner
Rc<T> - Reference counted, single-threaded
Arc<T> - Atomic reference counted, thread-safe
Mutex<T> - Mutual exclusion lock
RwLock<T> - Reader-writer lock
RefCell<T> - Runtime borrow checking
Cell<T> - Interior mutability for Copy types
#[derive(Debug, Clone, PartialEq, Eq, Hash)]
struct MyStruct {
field: String,
}
impl Default for MyStruct {
fn default() -> Self {
Self {
field: String::new(),
}
}
}
impl std::fmt::Display for MyStruct {
fn fmt(&self, f: &mut std::fmt::Formatter) -> std::fmt::Result {
write!(f, "MyStruct({})", self.field)
}
}
Tokio: Full-featured, most popular, excellent ecosystem
async-std: Mirrors std library API, simpler for beginners
smol: Lightweight, minimal dependencies
Skill Version : 1.0.0 Last Updated : October 2025 Skill Category : Systems Programming, Performance, Memory Safety Context7 Integration : Rust documentation and error code examples
Weekly Installs
63
Repository
GitHub Stars
47
First Seen
Jan 22, 2026
Security Audits
Gen Agent Trust HubFailSocketPassSnykPass
Installed on
gemini-cli47
cursor47
opencode47
codex44
claude-code42
github-copilot41
TanStack Query v5 完全指南:React 数据管理、乐观更新、离线支持
2,500 周安装
fn set_name(&mut self, name: impl Into<String>)