Struct scoped_tls::ScopedKey
source · [−]pub struct ScopedKey<T> { /* private fields */ }
Expand description
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
sourceimpl<T> ScopedKey<T>
impl<T> ScopedKey<T>
sourcepub fn set<F, R>(&'static self, t: &T, f: F) -> R where
F: FnOnce() -> R,
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 cb
is running, the value t
will be returned by get
unless
this function is called recursively inside of cb
.
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);
});
sourcepub fn with<F, R>(&'static self, f: F) -> R where
F: FnOnce(&T) -> R,
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`
});
Trait Implementations
Auto Trait Implementations
impl<T> RefUnwindSafe for ScopedKey<T> where
T: RefUnwindSafe,
impl<T> Send for ScopedKey<T> where
T: Send,
impl<T> Unpin for ScopedKey<T> where
T: Unpin,
impl<T> UnwindSafe for ScopedKey<T> where
T: UnwindSafe,
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