# Struct lock_api::RwLockWriteGuard [−] [src]

    #[must_use = "if unused the RwLock will immediately unlock"]pub struct RwLockWriteGuard<'a, R: RawRwLock, T: ?Sized> { /* fields omitted */ }

RAII structure used to release the exclusive write access of a lock when dropped.

## Implementations

### `impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> RwLockWriteGuard<'a, R, T>` [src]

#### `pub fn rwlock(s: &Self) -> &'a RwLock<R, T>` [src]

Returns a reference to the original reader-writer lock object.

#### `pub fn map<U: ?Sized, F>(s: Self, f: F) -> MappedRwLockWriteGuard<'a, R, U> where
F: FnOnce(&mut T) -> &mut U,` [src]

Make a new `MappedRwLockWriteGuard` for a component of the locked data.

This operation cannot fail as the `RwLockWriteGuard` passed in already locked the data.

This is an associated function that needs to be used as `RwLockWriteGuard::map(...)`. A method would interfere with methods of the same name on the contents of the locked data.

#### `pub fn try_map<U: ?Sized, F>(
s: Self,
f: F
) -> Result<MappedRwLockWriteGuard<'a, R, U>, Self> where
F: FnOnce(&mut T) -> Option<&mut U>,` [src]

Attempts to make a new `MappedRwLockWriteGuard` for a component of the locked data. The original guard is return if the closure returns `None`.

This operation cannot fail as the `RwLockWriteGuard` passed in already locked the data.

This is an associated function that needs to be used as `RwLockWriteGuard::map(...)`. A method would interfere with methods of the same name on the contents of the locked data.

#### `pub fn unlocked<F, U>(s: &mut Self, f: F) -> U where
F: FnOnce() -> U,` [src]

Temporarily unlocks the `RwLock` to execute the given function.

This is safe because `&mut` guarantees that there exist no other references to the data protected by the `RwLock`.

### `impl<'a, R: RawRwLockDowngrade + 'a, T: ?Sized + 'a> RwLockWriteGuard<'a, R, T>` [src]

#### `pub fn downgrade(s: Self) -> RwLockReadGuard<'a, R, T>` [src]

Atomically downgrades a write lock into a read lock without allowing any writers to take exclusive access of the lock in the meantime.

Note that if there are any writers currently waiting to take the lock then other readers may not be able to acquire the lock even if it was downgraded.

### `impl<'a, R: RawRwLockUpgradeDowngrade + 'a, T: ?Sized + 'a> RwLockWriteGuard<'a, R, T>` [src]

#### `pub fn downgrade_to_upgradable(s: Self) -> RwLockUpgradableReadGuard<'a, R, T>` [src]

Atomically downgrades a write lock into an upgradable read lock without allowing any writers to take exclusive access of the lock in the meantime.

Note that if there are any writers currently waiting to take the lock then other readers may not be able to acquire the lock even if it was downgraded.

### `impl<'a, R: RawRwLockFair + 'a, T: ?Sized + 'a> RwLockWriteGuard<'a, R, T>` [src]

#### `pub fn unlock_fair(s: Self)` [src]

Unlocks the `RwLock` using a fair unlock protocol.

By default, `RwLock` is unfair and allow the current thread to re-lock the `RwLock` before another has the chance to acquire the lock, even if that thread has been blocked on the `RwLock` for a long time. This is the default because it allows much higher throughput as it avoids forcing a context switch on every `RwLock` unlock. This can result in one thread acquiring a `RwLock` many more times than other threads.

However in some cases it can be beneficial to ensure fairness by forcing the lock to pass on to a waiting thread if there is one. This is done by using this method instead of dropping the `RwLockWriteGuard` normally.

#### `pub fn unlocked_fair<F, U>(s: &mut Self, f: F) -> U where
F: FnOnce() -> U,` [src]

Temporarily unlocks the `RwLock` to execute the given function.

The `RwLock` is unlocked a fair unlock protocol.

This is safe because `&mut` guarantees that there exist no other references to the data protected by the `RwLock`.

#### `pub fn bump(s: &mut Self)` [src]

Temporarily yields the `RwLock` to a waiting thread if there is one.

This method is functionally equivalent to calling `unlock_fair` followed by `write`, however it can be much more efficient in the case where there are no waiting threads.

## Trait Implementations

### `impl<'a, R: RawRwLock + 'a, T: Debug + ?Sized + 'a> Debug for RwLockWriteGuard<'a, R, T>` [src]

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

Formats the value using the given formatter. Read more

### `impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> Deref for RwLockWriteGuard<'a, R, T>` [src]

#### `type Target = T`

The resulting type after dereferencing.

#### `fn deref(&self) -> &T` [src]

Dereferences the value.

### `impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> DerefMut for RwLockWriteGuard<'a, R, T>` [src]

#### `fn deref_mut(&mut self) -> &mut T` [src]

Mutably dereferences the value.

### `impl<'a, R: RawRwLock + 'a, T: Display + ?Sized + 'a> Display for RwLockWriteGuard<'a, R, T>` [src]

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

Formats the value using the given formatter. Read more

### `impl<'a, R: RawRwLock + 'a, T: ?Sized + 'a> Drop for RwLockWriteGuard<'a, R, T>` [src]

#### `fn drop(&mut self)` [src]

Executes the destructor for this type. Read more

## Auto Trait Implementations

### `impl<'a, R, T: ?Sized> Send for RwLockWriteGuard<'a, R, T> where
R: Sync,
T: Send + Sync,
<R as RawRwLock>::GuardMarker: Send,`

### `impl<'a, R, T: ?Sized> Sync for RwLockWriteGuard<'a, R, T> where
R: Sync,
T: Send + Sync,
<R as RawRwLock>::GuardMarker: Sync,`

### `impl<'a, R, T: ?Sized> Unpin for RwLockWriteGuard<'a, R, T> where
<R as RawRwLock>::GuardMarker: Unpin,`

## Blanket Implementations

### `impl<T> Any for T where
T: 'static + ?Sized,` [src]

#### `pub fn type_id(&self) -> TypeId` [src]

Gets the `TypeId` of `self`. Read more

### `impl<T> Borrow<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow(&self) -> &T` [src]

Immutably borrows from an owned value. Read more

### `impl<T> BorrowMut<T> for T where
T: ?Sized,` [src]

#### `pub fn borrow_mut(&mut self) -> &mut T` [src]

Mutably borrows from an owned value. Read more

### `impl<T> From<T> for T` [src]

#### `pub fn from(t: T) -> T` [src]

Performs the conversion.

### `impl<T, U> Into<U> for T where
U: From<T>,` [src]

#### `pub fn into(self) -> U` [src]

Performs the conversion.

### `impl<T, U> TryFrom<U> for T where
U: Into<T>,` [src]

#### `type Error = Infallible`

The type returned in the event of a conversion error.

#### `pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>` [src]

Performs the conversion.

### `impl<T, U> TryInto<U> for T where
U: TryFrom<T>,` [src]

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

The type returned in the event of a conversion error.

#### `pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>` [src]

Performs the conversion.