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Update Termination trait docs #94486

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Update Termination trait docs #94486

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5 changes: 5 additions & 0 deletions library/std/src/process.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2030,6 +2030,11 @@ pub fn id() -> u32 {
///
/// The default implementations are returning `libc::EXIT_SUCCESS` to indicate
/// a successful execution. In case of a failure, `libc::EXIT_FAILURE` is returned.
///
/// Note that this trait is supposed to be used in standard library runtime,
/// where returned value from main function is considered meaningful.
/// On the other hand, implementing Termination in no-std environment, where
/// there is no notion of `exit status`, has no effect or may possibly cause bugs.
Comment on lines +2036 to +2037
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The issue isn't that it could lead to bugs, std::process::Termination and std::process::exit wouldn't be available in a no_std binary so there would be no way to misuse it. I believe the issue that @Lokathor wanted to clarify was that Termination is intended to be a piece of the standard library's runtime that is provided for convenience and should not be seen as a general requirement on what other runtime implementations must do.

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Yes. My concern is not that implementing Termination is ever an error/bug. Instead, I would just like the docs to be clear that how the value is interpreted when it's returned from main is not something to rely on in alternative runtimes.

#[cfg_attr(not(test), lang = "termination")]
#[unstable(feature = "termination_trait_lib", issue = "43301")]
#[rustc_on_unimplemented(
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