pub struct SyncLazy<T, F = fn() -> T> { /* private fields */ }Expand description
A value which is initialized on the first access.
This type is a thread-safe Lazy, and can be used in statics.
Examples
#![feature(once_cell)]
use std::collections::HashMap;
use std::lazy::SyncLazy;
static HASHMAP: SyncLazy<HashMap<i32, String>> = SyncLazy::new(|| {
    println!("initializing");
    let mut m = HashMap::new();
    m.insert(13, "Spica".to_string());
    m.insert(74, "Hoyten".to_string());
    m
});
fn main() {
    println!("ready");
    std::thread::spawn(|| {
        println!("{:?}", HASHMAP.get(&13));
    }).join().unwrap();
    println!("{:?}", HASHMAP.get(&74));
    // Prints:
    //   ready
    //   initializing
    //   Some("Spica")
    //   Some("Hoyten")
}Implementations
Trait Implementations
impl<T, F: UnwindSafe> RefUnwindSafe for SyncLazy<T, F> where
    SyncOnceCell<T>: RefUnwindSafe, 
impl<T, F: Send> Sync for SyncLazy<T, F> where
    SyncOnceCell<T>: Sync, 
impl<T, F: UnwindSafe> UnwindSafe for SyncLazy<T, F> where
    SyncOnceCell<T>: UnwindSafe, 
Auto Trait Implementations
impl<T, F> Send for SyncLazy<T, F> where
    F: Send,
    T: Send, 
impl<T, F> Unpin for SyncLazy<T, F> where
    F: Unpin,
    T: Unpin, 
Blanket Implementations
sourceimpl<T> BorrowMut<T> for T where
    T: ?Sized, 
 
impl<T> BorrowMut<T> for T where
    T: ?Sized, 
const: unstable · sourcefn borrow_mut(&mut self) -> &mut T
 
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more