Struct OnceNonZeroUsize

pub struct OnceNonZeroUsize { /* private fields */ }

A thread-safe cell which can be written to only once.

Implementations

impl OnceNonZeroUsize

pub const fn new() -> OnceNonZeroUsize

Creates a new empty cell.

pub fn get(&self) -> Option<NonZeroUsize>

Gets the underlying value.

pub fn set(&self, value: NonZeroUsize) -> Result<(), ()>

Sets the contents of this cell to value.

Returns Ok(()) if the cell was empty and Err(()) if it was full.

pub fn get_or_init<F>(&self, f: F) -> NonZeroUsize

where F: FnOnce() -> NonZeroUsize,

Gets the contents of the cell, initializing it with f if the cell was empty.

If several threads concurrently run get_or_init, more than one f can be called. However, all threads will return the same value, produced by some f.

pub fn get_or_try_init<F, E>(&self, f: F) -> Result<NonZeroUsize, E>

where F: FnOnce() -> Result<NonZeroUsize, E>,

Gets the contents of the cell, initializing it with f if the cell was empty. If the cell was empty and f failed, an error is returned.

If several threads concurrently run get_or_init, more than one f can be called. However, all threads will return the same value, produced by some f.

Trait Implementations

impl Debug for OnceNonZeroUsize

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for OnceNonZeroUsize

fn default() -> OnceNonZeroUsize

Returns the “default value” for a type.

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.

Size: 8 bytes