Module std::os::windows::io1.0.0[][src]

This is supported on Windows only.
Expand description

Windows-specific extensions to general I/O primitives.

Just like raw pointers, raw Windows handles and sockets point to resources with dynamic lifetimes, and they can dangle if they outlive their resources or be forged if they’re created from invalid values.

This module provides three types for representing raw handles and sockets with different ownership properties: raw, borrowed, and owned, which are analogous to types used for representing pointers:

TypeAnalogous to
RawHandle*const _
RawSocket*const _
BorrowedHandle<'a>&'a _
BorrowedSocket<'a>&'a _

Like raw pointers, RawHandle and RawSocket values are primitive values. And in new code, they should be considered unsafe to do I/O on (analogous to dereferencing them). Rust did not always provide this guidance, so existing code in the Rust ecosystem often doesn’t mark RawHandle and RawSocket usage as unsafe. Once the io_safety feature is stable, libraries will be encouraged to migrate, either by adding unsafe to APIs that dereference RawHandle and RawSocket values, or by using to BorrowedHandle, BorrowedSocket, OwnedHandle, or OwnedSocket.

Like references, BorrowedHandle and BorrowedSocket values are tied to a lifetime, to ensure that they don’t outlive the resource they point to. These are safe to use. BorrowedHandle and BorrowedSocket values may be used in APIs which provide safe access to any system call except for CloseHandle, closesocket, or any other call that would end the dynamic lifetime of the resource without ending the lifetime of the handle or socket.

Like boxes, OwnedHandle and OwnedSocket values conceptually own the resource they point to, and free (close) it when they are dropped.



A borrowed handle.


A borrowed socket.


FFI type for handles in return values or out parameters, where INVALID_HANDLE_VALUE is used as a sentry value to indicate errors, such as in the return value of CreateFileW. This uses repr(transparent) and has the representation of a host handle, so that it can be used in such FFI declarations.


An owned handle.


An owned socket.



A trait to borrow the handle from an underlying object.


A trait to borrow the socket from an underlying object.

Extracts raw handles.

Extracts raw sockets.

Construct I/O objects from raw handles.

Creates I/O objects from raw sockets.

A trait to express the ability to consume an object and acquire ownership of its raw HANDLE.

A trait to express the ability to consume an object and acquire ownership of its raw SOCKET.

Type Definitions