Struct CppLtRef 

pub struct CppLtRef<'a, T: ?Sized> { /* private fields */ }

A CppRef with an associated lifetime. This can be used in place of any CppRef due to a Deref implementation.

Implementations

impl<T: ?Sized> CppLtRef<'_, T>

pub fn lifetime_cast(&self) -> CppRef<T>

Extend the lifetime of the returned reference beyond normal Rust borrow checker rules.

Normally, a reference can’t be used beyond the lifetime of the object which gave it to you, but sometimes C++ APIs can return references to global or other longer-lived objects. In such a case you should use this method to get a longer-lived reference.

Usage

When you’re given a C++ reference and you know its referent is valid for a long time, use this method. Store the resulting CppRef somewhere in Rust with an equivalent lifetime.

Safety

Because CppRefs are never dereferenced in Rust, misuse of this API cannot lead to undefined behavior in Rust and is therefore not unsafe. Nevertheless this can lead to UB in C++, so use carefully.

pub fn from_ptr(ptr: *const T) -> Self

Create a C++ reference from a raw pointer.

Methods from Deref<Target = CppRef<T>>

pub fn as_ptr(&self) -> *const T

Retrieve the underlying C++ pointer.

pub unsafe fn as_ref(&self) -> &T

Get a regular Rust reference out of this C++ reference.

Safety

Callers must guarantee that the referent is not modified by any other C++ or Rust code while the returned reference exists. Callers must also guarantee that no mutable Rust reference is created to the referent while the returned reference exists.

Callers must also be sure that the C++ reference is properly aligned, not null, pointing to valid data, etc.

pub fn const_cast(&self) -> CppMutRef<T>

Create a mutable version of this reference, roughly equivalent to C++ const_cast.

The opposite is to use AsCppRef::as_cpp_ref on a CppMutRef to obtain a CppRef.

Safety

Because we never dereference a CppRef in Rust, this cannot create undefined behavior within Rust and is therefore not unsafe. It is however generally unwise, just as it is in C++. Use sparingly.

Trait Implementations

impl<T: ?Sized> Clone for CppLtRef<'_, T>

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl<T: ?Sized> Copy for CppLtRef<'_, T>

impl<T: ?Sized> Deref for CppLtRef<'_, T>

type Target = CppRef<T>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.