# Struct critical_section::RestoreState

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    pub struct RestoreState(_);

Expand description

Opaque “restore state”.

Implementations use this to “carry over” information between acquiring and releasing a critical section. For example, when nesting two critical sections of an implementation that disables interrupts globally, acquiring the inner one won’t disable the interrupts since they’re already disabled. The impl would use the restore state to “tell” the corresponding release that it does not have to reenable interrupts yet, only the outer release should do so.

User code uses `RestoreState` opaquely, critical section implementations use `RawRestoreState` so that they can use the inner value.

## Implementations§

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### impl RestoreState

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#### pub const fn invalid() -> Self

Create an invalid, dummy `RestoreState`.

This can be useful to avoid `Option` when storing a `RestoreState` in a struct field, or a `static`.

Note that due to the safety contract of `acquire`/`release`, you must not pass a `RestoreState` obtained from this method to `release`.

## Trait Implementations§

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### impl Clone for RestoreState

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#### fn clone(&self) -> RestoreState

Returns a copy of the value. Read more
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#### fn clone_from(&mut self, source: &Self)

Performs copy-assignment from `source`. Read more
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### impl Debug for RestoreState

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#### fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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### impl Copy for RestoreState

## Auto Trait Implementations§

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### impl RefUnwindSafe for RestoreState

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### impl Send for RestoreState

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### impl Sync for RestoreState

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### impl Unpin for RestoreState

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### impl UnwindSafe for RestoreState

## Blanket Implementations§

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### impl<T> Any for Twhere T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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### impl<T> Borrow<T> for Twhere T: ?Sized,

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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for Twhere T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T> From<T> for T

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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for Twhere U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `[From]<T> for U` chooses to do.

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### impl<T, U> TryFrom<U> for Twhere U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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### impl<T, U> TryInto<U> for Twhere U: TryFrom<T>,

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#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.