Struct scoped_tls_hkt::ScopedKeyMut

pub struct ScopedKeyMut<T: ?Sized + 'static> { /* fields omitted */ }

Type representing a thread local storage key corresponding to a mutable 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.

This differs from a ScopedKey because it provides access through a mutable reference. As a result, when the with(..) method is used to access the value, the key will appear unset whilst the closure is running. This is to prevent the value being borrowed a second time.

Methods

impl<T: ?Sized + 'static> ScopedKeyMut<T>

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

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

pub fn with<F, R>(&'static self, f: F) -> R where
    F: FnOnce(&mut T) -> R, 

Gets a value out of this scoped variable.

This function takes a closure which receives the value of this variable. For the duration of the closure, the key will appear unset.

Panics

This function will panic if set has not previously been called, or if the call is nested inside another (multiple mutable borrows of the same value are not allowed).

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

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

Trait Implementations

impl<T: ?Sized + 'static> Sync for ScopedKeyMut<T>