Struct core::ptr::DynMetadata
source · pub struct DynMetadata<Dyn: ?Sized> { /* private fields */ }
🔬This is a nightly-only experimental API. (
ptr_metadata
#81513)Expand description
The metadata for a Dyn = dyn SomeTrait
trait object type.
It is a pointer to a vtable (virtual call table) that represents all the necessary information to manipulate the concrete type stored inside a trait object. The vtable notably it contains:
- type size
- type alignment
- a pointer to the type’s
drop_in_place
impl (may be a no-op for plain-old-data) - pointers to all the methods for the type’s implementation of the trait
Note that the first three are special because they’re necessary to allocate, drop, and deallocate any trait object.
It is possible to name this struct with a type parameter that is not a dyn
trait object
(for example DynMetadata<u64>
) but not to obtain a meaningful value of that struct.
Implementations§
source§impl<Dyn: ?Sized> DynMetadata<Dyn>
impl<Dyn: ?Sized> DynMetadata<Dyn>
sourcepub fn size_of(self) -> usize
🔬This is a nightly-only experimental API. (ptr_metadata
#81513)
pub fn size_of(self) -> usize
ptr_metadata
#81513)Returns the size of the type associated with this vtable.
Trait Implementations§
source§impl<Dyn: ?Sized> Clone for DynMetadata<Dyn>
impl<Dyn: ?Sized> Clone for DynMetadata<Dyn>
source§impl<Dyn: ?Sized> Debug for DynMetadata<Dyn>
impl<Dyn: ?Sized> Debug for DynMetadata<Dyn>
source§impl<Dyn: ?Sized> Hash for DynMetadata<Dyn>
impl<Dyn: ?Sized> Hash for DynMetadata<Dyn>
source§impl<Dyn: ?Sized> Ord for DynMetadata<Dyn>
impl<Dyn: ?Sized> Ord for DynMetadata<Dyn>
source§impl<Dyn: ?Sized> PartialEq<DynMetadata<Dyn>> for DynMetadata<Dyn>
impl<Dyn: ?Sized> PartialEq<DynMetadata<Dyn>> for DynMetadata<Dyn>
source§impl<Dyn: ?Sized> PartialOrd<DynMetadata<Dyn>> for DynMetadata<Dyn>
impl<Dyn: ?Sized> PartialOrd<DynMetadata<Dyn>> for DynMetadata<Dyn>
1.0.0 · source§fn le(&self, other: &Rhs) -> bool
fn le(&self, other: &Rhs) -> bool
This method tests less than or equal to (for
self
and other
) and is used by the <=
operator. Read moreimpl<Dyn: ?Sized> Copy for DynMetadata<Dyn>
impl<Dyn: ?Sized> Eq for DynMetadata<Dyn>
impl<Dyn: ?Sized> Send for DynMetadata<Dyn>
impl<Dyn: ?Sized> Sync for DynMetadata<Dyn>
impl<Dyn: ?Sized> Unpin for DynMetadata<Dyn>
Auto Trait Implementations§
impl<Dyn> !RefUnwindSafe for DynMetadata<Dyn>
impl<Dyn> !UnwindSafe for DynMetadata<Dyn>
Blanket Implementations§
source§impl<T> BorrowMut<T> for Twhere
T: ?Sized,
impl<T> BorrowMut<T> for Twhere T: ?Sized,
source§fn borrow_mut(&mut self) -> &mut T
fn borrow_mut(&mut self) -> &mut T
Mutably borrows from an owned value. Read more