Location in std::panic - Rust (original) (raw)
pub struct Location<'a> { /* private fields */ }Expand description
A struct containing information about the location of a panic.
This structure is created by PanicHookInfo::location() and 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");§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.
1.46.0 (const: 1.79.0)
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;
/// ```
/// |1 |11 |21 |31 |41
/// +-|---------|---------|---------|---------|--------
/// 15 | #[track_caller]
/// 16 | fn new_location() -> &'static Location<'static> {
/// 17 | Location::caller()
/// | ------------------| the value of this expression depends on the caller,
/// | | since the function is marked #[track_caller]
/// 18 | }
/// ```
#[track_caller]
fn new_location() -> &'static Location<'static> {
Location::caller()
}
/// ```
/// |1 |5 |11 |21 |31 |41 |51
/// +-|---|-----|---------|---------|---------|---------|---
/// 29 | fn constant_location() -> &'static Location<'static> {
/// 30 | new_location()
/// | ^ any invocation of constant_location() points here,
/// | no matter the location it is called from
/// 31 | }
/// ```
fn constant_location() -> &'static Location<'static> {
new_location()
}
fn main() {
// |1 |5 |11 |21 |31 |41 |51
// +-|---|-----|---------|---------|---------|---------|---
// 29 | fn constant_location() -> &'static Location<'static> {
// 30 | new_location()
// | ^ `let constant` points here
// 31 | }
let constant = constant_location();
assert_eq!(constant.file(), file!());
assert_eq!((constant.line(), constant.column()), (30, 5));
let constant_2 = constant_location();
assert_eq!(
(constant.file(), constant.line(), constant.column()),
(constant_2.file(), constant_2.line(), constant_2.column())
);
// |1 |11 |16 |21 |31
// +-|---------|----|----|---------|------
// 55 | let here = new_location();
// | ^ `let here` points here, as `new_location()` is the callsite
// 56 | assert_eq!(here.file(), file!());
let here = new_location();
assert_eq!(here.file(), file!());
assert_eq!((here.line(), here.column()), (55, 16));
// |1 |11 |21 ||32 |41 |51
// +-|---------|---------|---------||--------|---------|------
// 64 | let yet_another_location = new_location();
// | ^ `let yet_another_location` points here
// 65 | assert_eq!(here.file(), yet_another_location.file());
let yet_another_location = new_location();
assert_eq!(here.file(), yet_another_location.file());
assert_ne!(
(here.line(), here.column()),
(yet_another_location.line(), yet_another_location.column())
);
}1.10.0 (const: 1.79.0)
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");1.92.0 (const: 1.92.0)
Returns the name of the source file as a nul-terminated CStr.
This is useful for interop with APIs that expect C/C++ __FILE__ orstd::source_location::file_name, both of which return a nul-terminated const char*.
1.10.0 (const: 1.79.0)
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");1.25.0 (const: 1.79.0)
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");1.10.0§
Returns a duplicate of the value. Read more
1.0.0§
Performs copy-assignment from source. Read more
1.10.0§
Formats the value using the given formatter. Read more
1.26.0§
Formats the value using the given formatter. Read more
1.10.0§
1.10.0§
1.21.0§
Compares and returns the maximum of two values. Read more
1.21.0§
Compares and returns the minimum of two values. Read more
1.50.0§
Restrict a value to a certain interval. Read more
1.10.0§
Tests for self and other values to be equal, and is used by ==.
1.0.0§
Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
1.10.0§
This method returns an ordering between self and other values if one exists. Read more
1.0.0§
Tests less than (for self and other) and is used by the < operator. Read more
1.0.0§
Tests less than or equal to (for self and other) and is used by the<= operator. Read more
1.0.0§
Tests greater than (for self and other) and is used by the >operator. Read more
1.0.0§
Tests greater than or equal to (for self and other) and is used by the >= operator. Read more
1.10.0§
1.10.0§
1.10.0§
1.10.0§
Immutably borrows from an owned value. Read more
Mutably borrows from an owned value. Read more
🔬This is a nightly-only experimental API. (clone_to_uninit #126799)
Performs copy-assignment from self to dest. Read more
Returns the argument unchanged.
Calls U::from(self).
That is, this conversion is whatever the implementation of[From](../convert/trait.From.html "trait std::convert::From")<T> for U chooses to do.
The resulting type after obtaining ownership.
Creates owned data from borrowed data, usually by cloning. Read more
Uses borrowed data to replace owned data, usually by cloning. Read more
Converts the given value to a String. Read more
The type returned in the event of a conversion error.
Performs the conversion.
The type returned in the event of a conversion error.
Performs the conversion.