Struct ScopedKey 

pub struct ScopedKey<T> { /* private fields */ }

Type representing a thread local storage key corresponding to a reference to the type parameter T.

Keys are statically allocated and can contain a reference to an instance of type T scoped to a particular lifetime. Keys provides two methods, set and with, both of which currently use closures to control the scope of their contents.

Implementations

impl<T> ScopedKey<T>

pub fn set<F, R>(&'static self, t: &T, f: F) -> R

where F: FnOnce() -> R,

Inserts a value into this scoped thread local storage slot for a duration of a closure.

While f is running, the value t will be returned by get unless this function is called recursively inside of f.

Upon return, this function will restore the previous value, if any was available.

Examples

#[macro_use]
extern crate scoped_tls;

scoped_thread_local!(static FOO: u32);

FOO.set(&100, || {
    let val = FOO.with(|v| *v);
    assert_eq!(val, 100);

    // set can be called recursively
    FOO.set(&101, || {
        // ...
    });

    // Recursive calls restore the previous value.
    let val = FOO.with(|v| *v);
    assert_eq!(val, 100);
});

pub fn with<F, R>(&'static self, f: F) -> R

where F: FnOnce(&T) -> R,

Gets a value out of this scoped variable.

This function takes a closure which receives the value of this variable.

Panics

This function will panic if set has not previously been called.

Examples

#[macro_use]
extern crate scoped_tls;

scoped_thread_local!(static FOO: u32);

FOO.with(|slot| {
    // work with `slot`
});

pub fn is_set(&'static self) -> bool

Test whether this TLS key has been set for the current thread.

Trait Implementations

impl<T> Sync for ScopedKey<T>

Layout

Note: Most layout information is completely unstable and may even differ between compilations. The only exception is types with certain repr(...) attributes. Please see the Rust Reference's “Type Layout” chapter for details on type layout guarantees.

Size: 8 bytes