Move first OnceLock example to LazyLock · model-checking/verify-rust-std@6d001c5 (original) (raw)
`@@ -29,34 +29,26 @@ union Data<T, F> {
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`/// # Examples
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`///
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`` /// Initialize static variables with LazyLock.
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``
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///
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```` /// ```
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``
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/// use std::collections::HashMap;
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``
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///
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`/// use std::sync::LazyLock;
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`///
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``
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/// static HASHMAP: LazyLock<HashMap<i32, String>> = LazyLock::new(|| {
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``
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/// println!("initializing");
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``
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/// let mut m = HashMap::new();
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``
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/// m.insert(13, "Spica".to_string());
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``
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/// m.insert(74, "Hoyten".to_string());
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``
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/// m
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/// // n.b. static items do not call [`Drop`] on program termination, so this won't be deallocated.
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/// // this is fine, as the OS can deallocate the terminated program faster than we can free memory
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/// // but tools like valgrind might report "memory leaks" as it isn't obvious this is intentional.
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/// static DEEP_THOUGHT: LazyLock<String> = LazyLock::new(|| {
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/// # mod another_crate {
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``
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/// # pub fn great_question() -> String { "42".to_string() }
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``
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/// # }
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``
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/// // M3 Ultra takes about 16 million years in --release config
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``
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/// another_crate::great_question()
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`/// });
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`///
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``
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/// fn main() {
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``
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/// println!("ready");
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``
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/// std::thread::spawn(|| {
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``
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/// println!("{:?}", HASHMAP.get(&13));
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``
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/// }).join().unwrap();
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``
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/// println!("{:?}", HASHMAP.get(&74));
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``
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///
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``
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/// // Prints:
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``
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/// // ready
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``
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/// // initializing
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``
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/// // Some("Spica")
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``
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/// // Some("Hoyten")
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``
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/// }
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/// // The `String` is built, stored in the `LazyLock`, and returned as `&String`.
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/// let _ = &*DEEP_THOUGHT;
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/// // The `String` is retrieved from the `LazyLock` and returned as `&String`.
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/// let _ = &*DEEP_THOUGHT;
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```` /// ```
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///
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`` /// Initialize fields with LazyLock.
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```` /// ```
````
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`/// use std::sync::LazyLock;
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