use std::error::Error;use std::fs::File;use std::io::Read;use std::path::Path; fn file_double<P: AsRef<Path>>(file_path: P) -> Result<i32, Box<Error>> { let mut file = try!(File::open(file_path)); let mut contents = String::new(); try!(file.read_to_string(&mut ...
if let Err(e) = std::fs::read_to_string("file.txt") { return Err(Error::from(e)); } // 或者直接构造一个错误信息 Ok(()) } 二、定义自定义Error类型并融合 在复杂的应用场景中,我们可能需要定义自己的Error类型以提供更丰富的错误信息。thiserror库通常会与anyhow一起使用,以方便地构建结构化...
use std::fs::File;use std::io::prelude::*;use std::io;struct Info{name:String,age:i32,rating:i32,}fnwrite_info(info:&Info)->io::Result<()>{// Early return on errorletmut file=match File::create("my_best_friends.txt"){Err(e)=>returnErr(e),Ok(f)=>f,};ifletErr(e)=file...
如果hello.txt 文件不存在,会打印"Failed to open the file."。 当然,我们在枚举类章节讲到的 if let 语法可以简化 match 语法块: 实例 usestd::fs::File; fnmain(){ letf=File::open("hello.txt"); ifletOk(file)=f{ println!("File opened successfully."); }else{ println!("Failed to open t...
let(stream,_)=listener.accept().await?;tokio::task::spawn(async move {iflet Err(err)=http1::Builder::new().serve_connection(stream,service_fn(hello)).await { println!("Error serving connection: {:?}",err);} });} } 1. 2. ...
Result类型鼓励开发者显式地处理错误,而不是简单地忽略它们。通过模式匹配或if let语句,开发者可以检查函数返回的结果,并对错误进行适当的处理。这种强制性的错误处理方式有助于避免潜在的程序崩溃和数据损坏。 fndivide(numerator:i32, denominator:i32)->Result<i32,String> {ifdenominator ==0{Err("Division by ...
if let Err(panic) = thread.join() { println!("Thread had an error: {:?}", panic); } } 我们利用AtomicUsize的store方法将它的值设置为0,然后用load方法获取到它的值,如果不是0,则程序一直空转。在store和load方法中,我们都用到了一个参数:Ordering::SeqCst,在声明中能看出来它也是属于atomic包。
let result = panic::catch_unwind(|| { panic!("crash"); }); if result.is_err() { println!("panic reover: {:#?}", result); } println!("exit ok!"); } 代码运行结果如下: thread 'main' panicked at 'crash', src/main.rs:4:9 ...
Rust的let声明的绑定是不可变的，所以下面的代码是错误：let x = 5; x = 10; // error: re-...
fn main() { if let x = 3 && true {} } (Playground) I think only the first error should be reported: Compiling playground v0.0.1 (/playground) error[E0658]: `let` expressions in this position are experimental --> src/main.rs:2:8 | 2 | if ...