Struct std::os::windows::io::HandleOrInvalid
#[repr(transparent)]pub struct HandleOrInvalid(_);
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.
The only thing you can usefully do with a HandleOrInvalid is to convert it into an OwnedHandle using its TryFrom implementation; this conversion takes care of the check for INVALID_HANDLE_VALUE. This ensures that such FFI calls cannot start using the handle without checking for INVALID_HANDLE_VALUE first.
If this holds a valid handle, it will close the handle on drop.
Trait Implementations
impl Debug for HandleOrInvalid
fn fmt(&self, f: &mut Formatter<'_>) -> Result
Formats the value using the given formatter. Read more
impl FromRawHandle for HandleOrInvalid
unsafe fn from_raw_handle(handle: RawHandle) -> Self
Constructs a new instance of Self from the given RawHandle returned from a Windows API that uses INVALID_HANDLE_VALUE to indicate failure, such as CreateFileW.
Use Option<OwnedHandle> instead of HandleOrInvalid for APIs that use null to indicate failure.
Safety
The resource pointed to by handle must be either open and otherwise unowned, or equal to INVALID_HANDLE_VALUE (-1). It must not be null. Note that not all Windows APIs use INVALID_HANDLE_VALUE for errors; see here for the full story.
impl TryFrom<HandleOrInvalid> for OwnedHandle
type Error = ()
The type returned in the event of a conversion error.
fn try_from(handle_or_invalid: HandleOrInvalid) -> Result<Self, ()>
Performs the conversion.
impl Send for HandleOrInvalid
impl Sync for HandleOrInvalid
Auto Trait Implementations
impl RefUnwindSafe for HandleOrInvalid
impl Unpin for HandleOrInvalid
impl UnwindSafe for HandleOrInvalid
Blanket Implementations
impl<T> From<T> for T
pub fn from(t: T) -> T
Performs the conversion.
pub fn into(self) -> U
Performs the conversion.
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
Performs the conversion.
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
Performs the conversion.
© 2010 The Rust Project Developers
Licensed under the Apache License, Version 2.0 or the MIT license, at your option.
https://doc.rust-lang.org/std/os/windows/io/struct.HandleOrInvalid.html