Global in alloc::alloc - Rust
Description: The global memory allocator.

## Global

# Struct Global

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    pub struct Global;

🔬This is a nightly-only experimental API. (`allocator_api` #32838)
Expand description

The global memory allocator.

This type implements the `Allocator` trait by forwarding calls to the allocator registered with the `#[global_allocator]` attribute if there is one, or the `std` crate’s default.

Note: while this type is unstable, the functionality it provides can be accessed through the free functions in `alloc`.

## Trait Implementations§

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### impl Allocator for Global

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#### fn allocate(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (`allocator_api` #32838)
Attempts to allocate a block of memory. Read more
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#### fn allocate_zeroed(&self, layout: Layout) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (`allocator_api` #32838)
Behaves like `allocate`, but also ensures that the returned memory is zero-initialized. Read more
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#### unsafe fn deallocate(&self, ptr: NonNull<u8>, layout: Layout)

🔬This is a nightly-only experimental API. (`allocator_api` #32838)
Deallocates the memory referenced by `ptr`. Read more
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#### unsafe fn grow( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (`allocator_api` #32838)
Attempts to extend the memory block. Read more
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#### unsafe fn grow_zeroed( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (`allocator_api` #32838)
Behaves like `grow`, but also ensures that the new contents are set to zero before being returned. Read more
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#### unsafe fn shrink( &self, ptr: NonNull<u8>, old_layout: Layout, new_layout: Layout, ) -> Result<NonNull<[u8]>, AllocError>

🔬This is a nightly-only experimental API. (`allocator_api` #32838)
Attempts to shrink the memory block. Read more
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#### fn by_ref(&self) -> &Self
where Self: Sized,

🔬This is a nightly-only experimental API. (`allocator_api` #32838)
Creates a “by reference” adapter for this instance of `Allocator`. Read more
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### impl Clone for Global

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#### fn clone(&self) -> Global

Returns a duplicate of the value. Read more
1.0.0 · Source§

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

Performs copy-assignment from `source`. Read more
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### impl Debug for Global

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#### fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter. Read more
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### impl Default for Global

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#### fn default() -> Global

Returns the “default value” for a type. Read more
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### impl Copy for Global

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### impl<T: ?Sized + Unsize<U>, U: ?Sized> DispatchFromDyn<Box<U>> for Box<T, Global>

## Auto Trait Implementations§

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### impl Freeze for Global

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### impl RefUnwindSafe for Global

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### impl Send for Global

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### impl Sync for Global

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### impl Unpin for Global

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### impl UnwindSafe for Global

## Blanket Implementations§

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### impl<T> Any for T
where T: 'static + ?Sized,

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#### fn type_id(&self) -> TypeId

Gets the `TypeId` of `self`. Read more
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### impl<T> Borrow<T> for T
where T: ?Sized,

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#### fn borrow(&self) -> &T

Immutably borrows from an owned value. Read more
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### impl<T> BorrowMut<T> for T
where T: ?Sized,

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#### fn borrow_mut(&mut self) -> &mut T

Mutably borrows from an owned value. Read more
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### impl<T> CloneToUninit for T
where T: Clone,

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#### unsafe fn clone_to_uninit(&self, dest: *mut u8)

🔬This is a nightly-only experimental API. (`clone_to_uninit` #126799)
Performs copy-assignment from `self` to `dest`. Read more
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### impl<T> From<T> for T

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#### fn from(t: T) -> T

Returns the argument unchanged.

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### impl<T, U> Into<U> for T
where U: From<T>,

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#### fn into(self) -> U

Calls `U::from(self)`.

That is, this conversion is whatever the implementation of `From<T> for U` chooses to do.

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### impl<T> ToOwned for T
where T: Clone,

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#### type Owned = T

The resulting type after obtaining ownership.
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#### fn to_owned(&self) -> T

Creates owned data from borrowed data, usually by cloning. Read more
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#### fn clone_into(&self, target: &mut T)

Uses borrowed data to replace owned data, usually by cloning. Read more
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### impl<T, U> TryFrom<U> for T
where U: Into<T>,

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#### type Error = Infallible

The type returned in the event of a conversion error.
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#### fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>

Performs the conversion.
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### impl<T, U> TryInto<U> for T
where U: TryFrom<T>,

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#### type Error = <U as TryFrom<T>>::Error

The type returned in the event of a conversion error.
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#### fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>

Performs the conversion.