Trait collections::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