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| -rw-r--r-- | library/std/src/thread/scoped.rs | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/library/std/src/thread/scoped.rs b/library/std/src/thread/scoped.rs index 4af58f1a380..c4847b529a3 100644 --- a/library/std/src/thread/scoped.rs +++ b/library/std/src/thread/scoped.rs @@ -107,6 +107,24 @@ impl ScopeData { /// a.push(4); /// assert_eq!(x, a.len()); /// ``` +/// +/// # Lifetimes +/// +/// Scoped threads involve two lifetimes: `'scope` and `'env`. +/// +/// The `'scope` lifetime represents the lifetime of the scope itself. +/// That is: the time during which new scoped threads may be spawned, +/// and also the time during which they might still be running. +/// Once this lifetime ends, all scoped threads are joined. +/// This lifetime starts within the `scope` function, before `f` (the argument to `scope`) starts. +/// It ends after `f` returns and all scoped threads have been joined, but before `scope` returns. +/// +/// The `'env` lifetime represents the lifetime of whatever is borrowed by the scoped threads. +/// This lifetime must outlast the call to `scope`, and thus cannot be smaller than `'scope`. +/// It can be as small as the call to `scope`, meaning that anything that outlives this call, +/// such as local variables defined right before the scope, can be borrowed by the scoped threads. +/// +/// The `'env: 'scope` bound is part of the definition of the `Scope` type. #[track_caller] pub fn scope<'env, F, T>(f: F) -> T where |