# ThreadRng in rand::rngs - Rust
A reference to the thread-local generator
Keywords: rust, rustlang, rust-lang, ThreadRng

# Struct rand::rngs::ThreadRng

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    pub struct ThreadRng { /* private fields */ }

Expand description

A reference to the thread-local generator

An instance can be obtained via `thread_rng` or via `ThreadRng::default()`. This handle is safe to use everywhere (including thread-local destructors), though it is recommended not to use inside a fork handler. The handle cannot be passed between threads (is not `Send` or `Sync`).

`ThreadRng` uses the same PRNG as `StdRng` for security and performance and is automatically seeded from `OsRng`.

Unlike `StdRng`, `ThreadRng` uses the `ReseedingRng` wrapper to reseed the PRNG from fresh entropy every 64 kiB of random data as well as after a fork on Unix (though not quite immediately; see documentation of `ReseedingRng`). Note that the reseeding is done as an extra precaution against side-channel attacks and mis-use (e.g. if somehow weak entropy were supplied initially). The PRNG algorithms used are assumed to be secure.

## Trait Implementations

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### impl Clone for ThreadRng

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

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 ThreadRng

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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 Default for ThreadRng

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#### fn default() -> ThreadRng

Returns the “default value” for a type. Read more

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### impl RngCore for ThreadRng

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#### fn next_u32(&mut self) -> u32

Return the next random `u32`. Read more

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#### fn next_u64(&mut self) -> u64

Return the next random `u64`. Read more

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#### fn fill_bytes(&mut self, dest: &mut [ u8 ])

Fill `dest` with random data. Read more

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#### fn try_fill_bytes(&mut self, dest: &mut [ u8 ]) -> Result<(), Error>

Fill `dest` entirely with random data. Read more

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### impl CryptoRng for ThreadRng

## Auto Trait Implementations

### impl !RefUnwindSafe for ThreadRng

### impl !Send for ThreadRng

### impl !Sync for ThreadRng

### impl Unpin for ThreadRng

### impl !UnwindSafe for ThreadRng

## Blanket Implementations

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### impl<T> Any for T where
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 T where
T: ?Sized,

const: unstable · source

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

Immutably borrows from an owned value. Read more

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### impl<T> BorrowMut<T> for T where
T: ?Sized,

const: unstable · source

#### 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 T where
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> ToOwned for T where
T: Clone,

#### type Owned = T

The resulting type after obtaining ownership.

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

Creates owned data from borrowed data, usually by cloning. Read more

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#### fn clone_into(&self, target: &mut T)

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

Uses borrowed data to replace owned data, usually by cloning. Read more

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

#### type Error = Infallible

The type returned in the event of a conversion error.

const: unstable · source

#### 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 T where
U: TryFrom<T>,

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

The type returned in the event of a conversion error.

const: unstable · source

#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.

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### impl<V, T> VZip<V> for T where
V: MultiLane<T>,

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