std::ops::Place - Rust
Description: API documentation for the Rust `Place` trait in crate `std`.
Keywords: rust, rustlang, rust-lang, Place

# Trait std::ops::Place [−] [src]

    pub trait Place<Data> where Data: ?Sized {
        fn pointer(&mut self) -> *mut Data;
    }

Unstable (`placement_new_protocol` #27779)

Both `in (PLACE) EXPR` and `box EXPR` desugar into expressions that allocate an intermediate "place" that holds uninitialized state. The desugaring evaluates EXPR, and writes the result at the address returned by the `pointer` method of this trait.

A `Place` can be thought of as a special representation for a hypothetical `&uninit` reference (which Rust cannot currently express directly). That is, it represents a pointer to uninitialized storage.

The client is responsible for two steps: First, initializing the payload (it can access its address via `pointer`). Second, converting the agent to an instance of the owning pointer, via the appropriate `finalize` method (see the `InPlace`.

If evaluating EXPR fails, then the destructor for the implementation of Place to clean up any intermediate state (e.g. deallocate box storage, pop a stack, etc).

## Required Methods

### `fn pointer(&mut self) -> *mut Data`

Unstable (`placement_new_protocol` #27779)

Returns the address where the input value will be written. Note that the data at this address is generally uninitialized, and thus one should use `ptr::write` for initializing it.

## Implementors

- `impl<T> Place<T> for IntermediateBox<T>`
- `impl<'a, T> Place<T> for FrontPlace<'a, T>`
- `impl<'a, T> Place<T> for BackPlace<'a, T>`

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