# Struct cargo::util::interning::STRING_CACHE

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    struct STRING_CACHE {
        __private_field: (),
    }

## Fields§

§`__private_field: ()`

## Methods from Deref<Target = Mutex<HashSet<&'static str>>>§

1.0.0 · source

#### pub fn lock(&self) -> Result<MutexGuard<'_, T>, PoisonError<MutexGuard<'_, T>>>

Acquires a mutex, blocking the current thread until it is able to do so.

This function will block the local thread until it is available to acquire the mutex. Upon returning, the thread is the only thread with the lock held. An RAII guard is returned to allow scoped unlock of the lock. When the guard goes out of scope, the mutex will be unlocked.

The exact behavior on locking a mutex in the thread which already holds the lock is left unspecified. However, this function will not return on the second call (it might panic or deadlock, for example).

##### Errors

If another user of this mutex panicked while holding the mutex, then this call will return an error once the mutex is acquired.

##### Panics

This function might panic when called if the lock is already held by the current thread.

##### Examples

    use std::sync::{Arc, Mutex};
    use std::thread;

    let mutex = Arc::new(Mutex::new(0));
    let c_mutex = Arc::clone(&mutex);

    thread::spawn(move || {
        *c_mutex.lock().unwrap() = 10;
    }).join().expect("thread::spawn failed");
    assert_eq!(*mutex.lock().unwrap(), 10);

1.0.0 · source

#### pub fn try_lock( &self ) -> Result<MutexGuard<'_, T>, TryLockError<MutexGuard<'_, T>>>

Attempts to acquire this lock.

If the lock could not be acquired at this time, then `Err` is returned. Otherwise, an RAII guard is returned. The lock will be unlocked when the guard is dropped.

This function does not block.

##### Errors

If another user of this mutex panicked while holding the mutex, then this call will return the `Poisoned` error if the mutex would otherwise be acquired.

If the mutex could not be acquired because it is already locked, then this call will return the `WouldBlock` error.

##### Examples

    use std::sync::{Arc, Mutex};
    use std::thread;

    let mutex = Arc::new(Mutex::new(0));
    let c_mutex = Arc::clone(&mutex);

    thread::spawn(move || {
        let mut lock = c_mutex.try_lock();
        if let Ok(ref mut mutex) = lock {
            **mutex = 10;
        } else {
            println!("try_lock failed");
        }
    }).join().expect("thread::spawn failed");
    assert_eq!(*mutex.lock().unwrap(), 10);

1.2.0 · source

#### pub fn is_poisoned(&self) -> bool

Determines whether the mutex is poisoned.

If another thread is active, the mutex can still become poisoned at any time. You should not trust a `false` value for program correctness without additional synchronization.

##### Examples

    use std::sync::{Arc, Mutex};
    use std::thread;

    let mutex = Arc::new(Mutex::new(0));
    let c_mutex = Arc::clone(&mutex);

    let _ = thread::spawn(move || {
        let _lock = c_mutex.lock().unwrap();
        panic!(); // the mutex gets poisoned
    }).join();
    assert_eq!(mutex.is_poisoned(), true);

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#### pub fn clear_poison(&self)

🔬This is a nightly-only experimental API. (`mutex_unpoison`)

Clear the poisoned state from a mutex

If the mutex is poisoned, it will remain poisoned until this function is called. This allows recovering from a poisoned state and marking that it has recovered. For example, if the value is overwritten by a known-good value, then the mutex can be marked as un-poisoned. Or possibly, the value could be inspected to determine if it is in a consistent state, and if so the poison is removed.

##### Examples

    #![feature(mutex_unpoison)]

    use std::sync::{Arc, Mutex};
    use std::thread;

    let mutex = Arc::new(Mutex::new(0));
    let c_mutex = Arc::clone(&mutex);

    let _ = thread::spawn(move || {
        let _lock = c_mutex.lock().unwrap();
        panic!(); // the mutex gets poisoned
    }).join();

    assert_eq!(mutex.is_poisoned(), true);
    let x = mutex.lock().unwrap_or_else(|mut e| {
        **e.get_mut() = 1;
        mutex.clear_poison();
        e.into_inner()
    });
    assert_eq!(mutex.is_poisoned(), false);
    assert_eq!(*x, 1);

## Trait Implementations§

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### impl Deref for STRING_CACHE

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#### type Target = Mutex<HashSet<&'static str, RandomState>>

The resulting type after dereferencing.
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#### fn deref(&self) -> &Mutex<HashSet<&'static str>>

Dereferences the value.
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### impl LazyStatic for STRING_CACHE

## Auto Trait Implementations§

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### impl RefUnwindSafe for STRING_CACHE

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### impl Send for STRING_CACHE

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### impl Sync for STRING_CACHE

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### impl Unpin for STRING_CACHE

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### impl UnwindSafe for STRING_CACHE

## 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> Same<T> for T

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#### type Output = T

Should always be `Self`
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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.
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### impl<V, T> VZip<V> for Twhere V: MultiLane<T>,

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#### fn vzip(self) -> V

## 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.

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