Auto merge of #129665 - matthiaskrgr:rollup-hy23k7d, r=matthiaskrgr

Rollup of 8 pull requests

Successful merges:

 - #129507 (make it possible to enable const_precise_live_drops per-function)
 - #129581 (exit: explain our expectations for the exit handlers registered in a Rust program)
 - #129634 (Fix tidy to allow `edition = "2024"` in `Cargo.toml`)
 - #129635 (Use unsafe extern blocks throughout the compiler)
 - #129645 (Fix typos in floating-point primitive type docs)
 - #129648 (More `unreachable_pub`)
 - #129649 (ABI compat check: detect unadjusted ABI mismatches)
 - #129652 (fix Pointer to reference conversion docs)

r? `@ghost`
`@rustbot` modify labels: rollup

1 files changed, 9 insertions, 0 deletions

diff --git a/library/std/src/process.rs b/library/std/src/process.rs
index 9ffdebe1b6f..bbea27ebc10 100644
--- a/library/std/src/process.rs
+++ b/library/std/src/process.rs
@@ -2296,6 +2296,15 @@ impl Child {
 /// }
 /// ```
 ///
+/// In its current implementation, this function will execute exit handlers registered with `atexit`
+/// as well as other platform-specific exit handlers (e.g. `fini` sections of ELF shared objects).
+/// This means that Rust requires that all exit handlers are safe to execute at any time. In
+/// particular, if an exit handler cleans up some state that might be concurrently accessed by other
+/// threads, it is required that the exit handler performs suitable synchronization with those
+/// threads. (The alternative to this requirement would be to not run exit handlers at all, which is
+/// considered undesirable. Note that returning from `main` also calls `exit`, so making `exit` an
+/// unsafe operation is not an option.)
+///
 /// ## Platform-specific behavior
 ///
 /// **Unix**: On Unix-like platforms, it is unlikely that all 32 bits of `exit`