# Function getrandom::getrandom

source · [−]

    pub fn getrandom(dest: &mut [u8]) -> Result<(), Error>

Expand description

Fill `dest` with random bytes from the system’s preferred random number source.

This function returns an error on any failure, including partial reads. We make no guarantees regarding the contents of `dest` on error. If `dest` is empty, `getrandom` immediately returns success, making no calls to the underlying operating system.

Blocking is possible, at least during early boot; see module documentation.

In general, `getrandom` will be fast enough for interactive usage, though significantly slower than a user-space CSPRNG; for the latter consider `rand::thread_rng`.