pub struct OsRng;
Expand description
A random number generator that retrieves randomness from the operating system.
This is a zero-sized struct. It can be freely constructed with OsRng
.
The implementation is provided by the getrandom crate. Refer to getrandom documentation for details.
This struct is only available when specifying the crate feature getrandom
or std
. When using the rand
lib, it is also available as rand::rngs::OsRng
.
§Blocking and error handling
It is possible that when used during early boot the first call to OsRng
will block until the system’s RNG is initialised. It is also possible
(though highly unlikely) for OsRng
to fail on some platforms, most
likely due to system mis-configuration.
After the first successful call, it is highly unlikely that failures or significant delays will occur (although performance should be expected to be much slower than a user-space PRNG).
§Usage example
use rand_core::{RngCore, OsRng};
let mut key = [0u8; 16];
OsRng.fill_bytes(&mut key);
let random_u64 = OsRng.next_u64();
Trait Implementations§
Source§impl RngCore for OsRng
impl RngCore for OsRng
Source§fn fill_bytes(&mut self, dest: &mut [u8])
fn fill_bytes(&mut self, dest: &mut [u8])
dest
with random data. Read moreimpl Copy for OsRng
impl CryptoRng for OsRng
Auto Trait Implementations§
impl Freeze for OsRng
impl RefUnwindSafe for OsRng
impl Send for OsRng
impl Sync for OsRng
impl Unpin for OsRng
impl UnwindSafe for OsRng
Blanket Implementations§
Source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere
T: ?Sized,
Source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Source§impl<T> CloneToUninit for Twhere
T: Clone,
impl<T> CloneToUninit for Twhere
T: Clone,
Source§impl<T> CryptoRngCore for T
impl<T> CryptoRngCore for T
Source§impl<R> Rng for R
impl<R> Rng for R
Source§fn gen<T>(&mut self) -> Twhere
Standard: Distribution<T>,
fn gen<T>(&mut self) -> Twhere
Standard: Distribution<T>,
Source§fn gen_range<T, R>(&mut self, range: R) -> Twhere
T: SampleUniform,
R: SampleRange<T>,
fn gen_range<T, R>(&mut self, range: R) -> Twhere
T: SampleUniform,
R: SampleRange<T>,
Source§fn sample<T, D: Distribution<T>>(&mut self, distr: D) -> T
fn sample<T, D: Distribution<T>>(&mut self, distr: D) -> T
Source§fn sample_iter<T, D>(self, distr: D) -> DistIter<D, Self, T> ⓘwhere
D: Distribution<T>,
Self: Sized,
fn sample_iter<T, D>(self, distr: D) -> DistIter<D, Self, T> ⓘwhere
D: Distribution<T>,
Self: Sized,
Source§fn gen_bool(&mut self, p: f64) -> bool
fn gen_bool(&mut self, p: f64) -> bool
p
of being true. Read moreSource§fn gen_ratio(&mut self, numerator: u32, denominator: u32) -> bool
fn gen_ratio(&mut self, numerator: u32, denominator: u32) -> bool
numerator/denominator
of being
true. I.e. gen_ratio(2, 3)
has chance of 2 in 3, or about 67%, of
returning true. If numerator == denominator
, then the returned value
is guaranteed to be true
. If numerator == 0
, then the returned
value is guaranteed to be false
. Read more