Struct std::panic::Location

1.10.0 · source ·

pub struct Location<'a> { /* private fields */ }

Expand description

包含有关 panic 位置信息的结构体。

该结构体由 PanicInfo::location() 创建。

Examples

use std::panic;

panic::set_hook(Box::new(|panic_info| {
    if let Some(location) = panic_info.location() {
        println!("panic occurred in file '{}' at line {}", location.file(), location.line());
    } else {
        println!("panic occurred but can't get location information...");
    }
}));

panic!("Normal panic");

Run

Comparisons

在文件，行和列优先级中进行相等性和顺序的比较。文件被比较为字符串，而不是 Path，这可能是意外的。有关更多讨论，请参见 Location::file 的文档。

Implementations§

source §

impl<'a> Location<'a>

1.46.0 (const: unstable) · source

pub fn caller() -> &'static Location<'static>

返回此函数的调用者的源位置。如果该函数的调用者被注释，那么它的调用位置将被返回，以此类推，直到堆栈中第一个未被跟踪的函数体中的调用。

Examples

use std::panic::Location;

/// 返回调用它的 [`Location`]。
#[track_caller]
fn get_caller_location() -> &'static Location<'static> {
    Location::caller()
}

/// 从此函数的定义中返回 [`Location`]。
fn get_just_one_location() -> &'static Location<'static> {
    get_caller_location()
}

let fixed_location = get_just_one_location();
assert_eq!(fixed_location.file(), file!());
assert_eq!(fixed_location.line(), 14);
assert_eq!(fixed_location.column(), 5);

// 在不同的位置运行相同的未跟踪函数会得到相同的结果
let second_fixed_location = get_just_one_location();
assert_eq!(fixed_location.file(), second_fixed_location.file());
assert_eq!(fixed_location.line(), second_fixed_location.line());
assert_eq!(fixed_location.column(), second_fixed_location.column());

let this_location = get_caller_location();
assert_eq!(this_location.file(), file!());
assert_eq!(this_location.line(), 28);
assert_eq!(this_location.column(), 21);

// 在其他位置运行跟踪的函数会产生不同的值
let another_location = get_caller_location();
assert_eq!(this_location.file(), another_location.file());
assert_ne!(this_location.line(), another_location.line());
assert_ne!(this_location.column(), another_location.column());

Run

const: unstable · source

pub fn file(&self) -> &str

返回 panic 源自的源文件的名称。

`&str`，不是 `&Path`

返回的名称指向编译系统上的源路径，但是将其直接表示为 &Path 是无效的。与提供内容的系统相比，编译后的代码可以在具有不同 Path 实现的不同系统上运行，并且此库当前没有不同的 “host path” 类型。

当通过模块系统中的多个路径可访问 “the same” 文件时 (通常使用 #[path = "..."] 属性或类似属性)，会发生最令人惊讶的行为，这可能导致看似相同的代码返回与此函数不同的值。

Cross-compilation

当主机平台和目标平台不同时，此值不适合传递给 Path::new 或类似的构造函数。

Examples

use std::panic;

panic::set_hook(Box::new(|panic_info| {
    if let Some(location) = panic_info.location() {
        println!("panic occurred in file '{}'", location.file());
    } else {
        println!("panic occurred but can't get location information...");
    }
}));

panic!("Normal panic");

Run

const: unstable · source

pub fn line(&self) -> u32

返回 panic 起源的行号。

Examples

use std::panic;

panic::set_hook(Box::new(|panic_info| {
    if let Some(location) = panic_info.location() {
        println!("panic occurred at line {}", location.line());
    } else {
        println!("panic occurred but can't get location information...");
    }
}));

panic!("Normal panic");

Run

1.25.0 (const: unstable) · source

pub fn column(&self) -> u32

返回 panic 起源的列。

Examples

use std::panic;

panic::set_hook(Box::new(|panic_info| {
    if let Some(location) = panic_info.location() {
        println!("panic occurred at column {}", location.column());
    } else {
        println!("panic occurred but can't get location information...");
    }
}));

panic!("Normal panic");

Run