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Struct std::process::ExitCode

pub struct ExitCode(/* private fields */);

This type represents the status code the current process can return to its parent under normal termination.

ExitCode is intended to be consumed only by the standard library (via Termination::report()), and intentionally does not provide accessors like PartialEq, Eq, or Hash. Instead the standard library provides the canonical SUCCESS and FAILURE exit codes as well as From<u8> for ExitCode for constructing other arbitrary exit codes.

Portability

Numeric values used in this type don’t have portable meanings, and different platforms may mask different amounts of them.

For the platform’s canonical successful and unsuccessful codes, see the SUCCESS and FAILURE associated items.

Differences from ExitStatus

ExitCode is intended for terminating the currently running process, via the Termination trait, in contrast to ExitStatus, which represents the termination of a child process. These APIs are separate due to platform compatibility differences and their expected usage; it is not generally possible to exactly reproduce an ExitStatus from a child for the current process after the fact.

Examples

ExitCode can be returned from the main function of a crate, as it implements Termination:

use std::process::ExitCode;

fn main() -> ExitCode {
    if !check_foo() {
        return ExitCode::from(42);
    }

    ExitCode::SUCCESS
}

Implementations

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impl ExitCode
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pub const SUCCESS: ExitCode = _

The canonical ExitCode for successful termination on this platform.

Note that a ()-returning main implicitly results in a successful termination, so there’s no need to return this from main unless you’re also returning other possible codes.

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pub const FAILURE: ExitCode = _

The canonical ExitCode for unsuccessful termination on this platform.

If you’re only returning this and SUCCESS from main, consider instead returning Err(_) and Ok(()) respectively, which will return the same codes (but will also eprintln! the error).

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pub fn exit_process(self) -> !
🔬This is a nightly-only experimental API. (exitcode_exit_method #97100)

Exit the current process with the given ExitCode.

Note that this has the same caveats as process::exit(), namely that this function terminates the process immediately, so no destructors on the current stack or any other thread’s stack will be run. If a clean shutdown is needed, it is recommended to simply return this ExitCode from the main function, as demonstrated in the type documentation.

Differences from process::exit()

process::exit() accepts any i32 value as the exit code for the process; however, there are platforms that only use a subset of that value (see process::exit platform-specific behavior). ExitCode exists because of this; only ExitCodes that are supported by a majority of our platforms can be created, so those problems don’t exist (as much) with this method.

Examples
#![feature(exitcode_exit_method)]
// there's no way to gracefully recover from an UhOhError, so we just
// print a message and exit
fn handle_unrecoverable_error(err: UhOhError) -> ! {
    eprintln!("UH OH! {err}");
    let code = match err {
        UhOhError::GenericProblem => ExitCode::FAILURE,
        UhOhError::Specific => ExitCode::from(3),
        UhOhError::WithCode { exit_code, .. } => exit_code,
    };
    code.exit_process()
}

Trait Implementations

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impl Clone for ExitCode
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fn clone(&self) -> ExitCode
Returns a copy of the value. Read more
1.0.0source 
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source. Read more
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impl Debug for ExitCode
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fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
1.75.0source 
impl Default for ExitCode

The default value is ExitCode::SUCCESS

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fn default() -> Self
Returns the “default value” for a type. Read more
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impl ExitCodeExt for ExitCodeAvailable on Windows only.
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fn from_raw(raw: u32) -> Self
🔬This is a nightly-only experimental API. (windows_process_exit_code_from)
Creates a new ExitCode from the raw underlying u32 return value of a process. Read more
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impl From<u8> for ExitCode
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fn from(code: u8) -> Self

Construct an ExitCode from an arbitrary u8 value.

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impl Termination for ExitCode
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fn report(self) -> ExitCode
Is called to get the representation of the value as status code. This status code is returned to the operating system.
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impl Copy for ExitCode

Auto Trait Implementations

impl RefUnwindSafe for ExitCode
impl Send for ExitCode
impl Sync for ExitCode
impl Unpin for ExitCode
impl UnwindSafe for ExitCode

Blanket Implementations

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impl<T> Any for T
where
    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 T
where
    T: ?Sized,
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fn borrow(&self) -> &T
Immutably borrows from an owned value. Read more
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impl<T> BorrowMut<T> for T
where
    T: ?Sized,
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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
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fn from(t: T) -> T

Returns the argument unchanged.

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impl<T, U> Into<U> for T
where
    U: From<T>,
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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 T
where
    T: Clone,
 
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, U> TryFrom<U> for T
where
    U: Into<T>,
 
type Error = Infallible
The type returned in the event of a conversion error.
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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 T
where
    U: TryFrom<T>,
 
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
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fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
Performs the conversion.

© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/process/struct.ExitCode.html