Struct std::panic::Location

1.10.0 · source ·
pub struct Location<'a> { /* private fields */ }
Expand description

A struct containing information about the location of a panic.

This structure is created by PanicInfo::location().

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

Comparisons for equality and ordering are made in file, line, then column priority. Files are compared as strings, not Path, which could be unexpected. See Location::file’s documentation for more discussion.

Implementations§

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impl<'a> Location<'a>

1.46.0 (const: unstable) · source

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

Returns the source location of the caller of this function. If that function’s caller is annotated then its call location will be returned, and so on up the stack to the first call within a non-tracked function body.

Examples
use std::panic::Location;

/// Returns the [`Location`] at which it is called.
#[track_caller]
fn get_caller_location() -> &'static Location<'static> {
    Location::caller()
}

/// Returns a [`Location`] from within this function's definition.
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);

// running the same untracked function in a different location gives us the same result
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);

// running the tracked function in a different location produces a different value
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

Returns the name of the source file from which the panic originated.

&str, not &Path

The returned name refers to a source path on the compiling system, but it isn’t valid to represent this directly as a &Path. The compiled code may run on a different system with a different Path implementation than the system providing the contents and this library does not currently have a different “host path” type.

The most surprising behavior occurs when “the same” file is reachable via multiple paths in the module system (usually using the #[path = "..."] attribute or similar), which can cause what appears to be identical code to return differing values from this function.

Cross-compilation

This value is not suitable for passing to Path::new or similar constructors when the host platform and target platform differ.

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

Returns the line number from which the panic originated.

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

Returns the column from which the panic originated.

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

Trait Implementations§

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impl<'a> Clone for Location<'a>

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fn clone(&self) -> Location<'a>

Returns a copy of the value. Read more
1.0.0 · source§

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source. Read more
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impl<'a> Debug for Location<'a>

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fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
1.26.0 · source§

impl Display for Location<'_>

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fn fmt(&self, formatter: &mut Formatter<'_>) -> Result<(), Error>

Formats the value using the given formatter. Read more
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impl<'a> Hash for Location<'a>

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fn hash<__H>(&self, state: &mut __H)where
    __H: Hasher,

Feeds this value into the given Hasher. Read more
1.3.0 · source§

fn hash_slice<H>(data: &[Self], state: &mut H)where
    H: Hasher,
    Self: Sized,

Feeds a slice of this type into the given Hasher. Read more
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impl<'a> Ord for Location<'a>

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fn cmp(&self, other: &Location<'a>) -> Ordering

This method returns an Ordering between self and other. Read more
1.21.0 · source§

fn max(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the maximum of two values. Read more
1.21.0 · source§

fn min(self, other: Self) -> Selfwhere
    Self: Sized,

Compares and returns the minimum of two values. Read more
1.50.0 · source§

fn clamp(self, min: Self, max: Self) -> Selfwhere
    Self: Sized + PartialOrd<Self>,

Restrict a value to a certain interval. Read more
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impl<'a> PartialEq<Location<'a>> for Location<'a>

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fn eq(&self, other: &Location<'a>) -> bool

This method tests for self and other values to be equal, and is used by ==.
1.0.0 · source§

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
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impl<'a> PartialOrd<Location<'a>> for Location<'a>

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fn partial_cmp(&self, other: &Location<'a>) -> Option<Ordering>

This method returns an ordering between self and other values if one exists. Read more
1.0.0 · source§

fn lt(&self, other: &Rhs) -> bool

This method tests less than (for self and other) and is used by the < operator. Read more
1.0.0 · source§

fn le(&self, other: &Rhs) -> bool

This method tests less than or equal to (for self and other) and is used by the <= operator. Read more
1.0.0 · source§

fn gt(&self, other: &Rhs) -> bool

This method tests greater than (for self and other) and is used by the > operator. Read more
1.0.0 · source§

fn ge(&self, other: &Rhs) -> bool

This method tests greater than or equal to (for self and other) and is used by the >= operator. Read more
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impl<'a> Copy for Location<'a>

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impl<'a> Eq for Location<'a>

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impl<'a> StructuralEq for Location<'a>

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impl<'a> StructuralPartialEq for Location<'a>

Auto Trait Implementations§

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impl<'a> RefUnwindSafe for Location<'a>

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impl<'a> Send for Location<'a>

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impl<'a> Sync for Location<'a>

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impl<'a> Unpin for Location<'a>

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impl<'a> UnwindSafe for Location<'a>

Blanket Implementations§

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impl<T> Any for Twhere
    T: 'static + ?Sized,

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fn type_id(&self) -> TypeId

Gets the TypeId of self. Read more
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impl<T> Borrow<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for Twhere
    T: ?Sized,

const: unstable · source§

fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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impl<T> From<T> for T

const: unstable · source§

fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for Twhere
    U: From<T>,

const: unstable · source§

fn into(self) -> U

Calls U::from(self).

That is, this conversion is whatever the implementation of From<T> for U chooses to do.

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impl<T> ToOwned for Twhere
    T: Clone,

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type Owned = T

The resulting type after obtaining ownership.
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fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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impl<T> ToString for Twhere
    T: Display + ?Sized,

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default fn to_string(&self) -> String

Converts the given value to a String. Read more
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impl<T, U> TryFrom<U> for Twhere
    U: Into<T>,

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type Error = Infallible

The type returned in the event of a conversion error.
const: unstable · source§

fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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impl<T, U> TryInto<U> for Twhere
    U: TryFrom<T>,

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type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
const: unstable · source§

fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.