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| author | kennytm <kennytm@gmail.com> | 2018-08-04 14:35:59 +0800 |
|---|---|---|
| committer | GitHub <noreply@github.com> | 2018-08-04 14:35:59 +0800 |
| commit | 43410981ae51c0af24c4657e3cc7cd4a01d41a95 (patch) | |
| tree | 8cefe5f682037d3a4080ce5051aa8585328161b3 | |
| parent | aeb20284817497a895fee5a22b0013acd0a430e2 (diff) | |
| parent | a2f9aaf7a35e673c3b8f0825a07505b0294aa24f (diff) | |
| download | rust-43410981ae51c0af24c4657e3cc7cd4a01d41a95.tar.gz rust-43410981ae51c0af24c4657e3cc7cd4a01d41a95.zip | |
Rollup merge of #53024 - matklad:patch-1, r=alexcrichton
Specify reentrancy gurantees of `Once::call_once`
I don't think the docs are clear about what happens in the following code
```rust
static INIT: Once = ONCE_INIT;
INIT.call_once(|| INIT.call_once(|| println!("huh?")));
```
[Playground](https://play.rust-lang.org/?gist=15dde1f68a6ede263c7250c36977eade&version=stable&mode=debug&edition=2015)
Let's "specify" the behavior to make it clear that the current behavior (deadlock I think?) is not a strict guarantee.
| -rw-r--r-- | src/libstd/sync/once.rs | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/src/libstd/sync/once.rs b/src/libstd/sync/once.rs index 10282ecb658..3abc260b458 100644 --- a/src/libstd/sync/once.rs +++ b/src/libstd/sync/once.rs @@ -178,6 +178,10 @@ impl Once { /// happens-before relation between the closure and code executing after the /// return). /// + /// If the given closure recusively invokes `call_once` on the same `Once` + /// instance the exact behavior is not specified, allowed outcomes are + /// a panic or a deadlock. + /// /// # Examples /// /// ``` |