Struct std::ptr::DynMetadata
pub struct DynMetadata<Dyn>
where
Dyn: ?Sized,{ /* private fields */ }🔬This is a nightly-only experimental API. (
ptr_metadata #81513)
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_placeimpl (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
impl<Dyn> DynMetadata<Dyn>
where
Dyn: ?Sized,pub fn size_of(self) -> usize🔬This is a nightly-only experimental API. (
ptr_metadata #81513)
Returns the size of the type associated with this vtable.
pub fn align_of(self) -> usize🔬This is a nightly-only experimental API. (
ptr_metadata #81513)
Returns the alignment of the type associated with this vtable.
pub fn layout(self) -> Layout🔬This is a nightly-only experimental API. (
ptr_metadata #81513)
Returns the size and alignment together as a Layout
Trait Implementations
impl<Dyn> Clone for DynMetadata<Dyn>
where
Dyn: ?Sized,fn clone(&self) -> DynMetadata<Dyn>
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
Performs copy-assignment from
source. Read more
impl<Dyn> Debug for DynMetadata<Dyn>
where
Dyn: ?Sized,fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
impl<Dyn> Hash for DynMetadata<Dyn>
where
Dyn: ?Sized,fn hash<H>(&self, hasher: &mut H)
where
H: Hasher,fn hash_slice<H>(data: &[Self], state: &mut H)
where
H: Hasher,
Self: Sized,impl<Dyn> Ord for DynMetadata<Dyn>
where
Dyn: ?Sized,fn cmp(&self, other: &DynMetadata<Dyn>) -> Orderingfn max(self, other: Self) -> Self
where
Self: Sized,
Compares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self
where
Self: Sized,
Compares and returns the minimum of two values. Read more
fn clamp(self, min: Self, max: Self) -> Self
where
Self: Sized + PartialOrd,
Restrict a value to a certain interval. Read more
impl<Dyn> PartialEq for DynMetadata<Dyn>
where
Dyn: ?Sized,fn eq(&self, other: &DynMetadata<Dyn>) -> bool
This method tests for
self and other values to be equal, and is used by ==.
fn ne(&self, other: &Rhs) -> bool
This method tests for
!=. The default implementation is almost always sufficient, and should not be overridden without very good reason.
impl<Dyn> PartialOrd for DynMetadata<Dyn>
where
Dyn: ?Sized,fn partial_cmp(&self, other: &DynMetadata<Dyn>) -> Option<Ordering>fn lt(&self, other: &Rhs) -> boolfn le(&self, other: &Rhs) -> bool
This method tests less than or equal to (for
self and other) and is used by the <= operator. Read more
fn gt(&self, other: &Rhs) -> boolfn ge(&self, other: &Rhs) -> bool
This method tests greater than or equal to (for
self and other) and is used by the >= operator. Read more
impl<Dyn> Copy for DynMetadata<Dyn>
where
Dyn: ?Sized,impl<Dyn> Eq for DynMetadata<Dyn>
where
Dyn: ?Sized,impl<Dyn> Send for DynMetadata<Dyn>
where
Dyn: ?Sized,impl<Dyn> Sync for DynMetadata<Dyn>
where
Dyn: ?Sized,impl<Dyn> Unpin for DynMetadata<Dyn>
where
Dyn: ?Sized,Auto Trait Implementations
impl<Dyn> !RefUnwindSafe for DynMetadata<Dyn>impl<Dyn> !UnwindSafe for DynMetadata<Dyn>Blanket Implementations
impl<T> Any for T
where
T: 'static + ?Sized,impl<T> Borrow<T> for T
where
T: ?Sized,impl<T> BorrowMut<T> for T
where
T: ?Sized,impl<T> From<T> for Tfn from(t: T) -> TReturns the argument unchanged.
impl<T, U> Into<U> for T
where
U: From<T>,fn into(self) -> UCalls U::from(self).
That is, this conversion is whatever the implementation of From<T> for U chooses to do.
impl<T> ToOwned for T
where
T: Clone,type Owned = T
The resulting type after obtaining ownership.
fn to_owned(&self) -> T
Creates owned data from borrowed data, usually by cloning. Read more
fn clone_into(&self, target: &mut T)
Uses borrowed data to replace owned data, usually by cloning. Read more
impl<T, U> TryFrom<U> for T
where
U: Into<T>,type Error = Infallible
The type returned in the event of a conversion error.
fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
Performs the conversion.
impl<T, U> TryInto<U> for T
where
U: TryFrom<T>,type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
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/ptr/struct.DynMetadata.html