Struct std::ptr::DynMetadata
pub struct DynMetadata<Dyn> where Dyn: ?Sized, { /* fields omitted */ }
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
pub fn size_of(self) -> usize
Returns the size of the type associated with this vtable.
pub fn align_of(self) -> usize
Returns the alignment of the type associated with this vtable.
pub fn layout(self) -> Layout
Returns the size and alignment together as a Layout
Trait Implementations
pub 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
pub fn fmt(&self, f: &mut Formatter<'_>) -> Result<(), Error>
Formats the value using the given formatter. Read more
pub fn cmp(&self, other: &DynMetadata<Dyn>) -> Ordering
fn max(self, other: Self) -> Self
Compares and returns the maximum of two values. Read more
fn min(self, other: Self) -> Self
Compares and returns the minimum of two values. Read more
fn clamp(self, min: Self, max: Self) -> Self
Restrict a value to a certain interval. Read more
pub fn eq(&self, other: &DynMetadata<Dyn>) -> bool
This method tests for self and other values to be equal, and is used by ==. Read more
fn ne(&self, other: &Rhs) -> bool
This method tests for !=.
pub fn partial_cmp(&self, other: &DynMetadata<Dyn>) -> Option<Ordering>
This method returns an ordering between self and other values if one exists. Read more
fn lt(&self, other: &Rhs) -> bool
This method tests less than (for self and other) and is used by the < operator. Read more
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 more
fn gt(&self, other: &Rhs) -> bool
This method tests greater than (for self and other) and is used by the > operator. Read more
fn 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
Auto Trait Implementations
impl<Dyn: ?Sized> RefUnwindSafe for DynMetadata<Dyn> where
Dyn: RefUnwindSafe,
impl<Dyn: ?Sized> UnwindSafe for DynMetadata<Dyn> where
Dyn: UnwindSafe,
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 Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
Creates owned data from borrowed data, usually by cloning. Read more
pub fn clone_into(&self, target: &mut T)
toowned_clone_into #41263)recently added
Uses borrowed data to replace owned data, usually by cloning. Read more
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/ptr/struct.DynMetadata.html