Struct std::alloc::Global

pub struct Global;

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

The global memory allocator.

This type implements the Alloc 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

impl Copy for Global

impl Clone for Global

fn clone(&self) -> Global

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Default for Global

fn default() -> Global

Returns the "default value" for a type.

impl Debug for Global

fn fmt(&self, f: &mut Formatter) -> Result<(), Error>

Formats the value using the given formatter.

impl Alloc for Global

unsafe fn alloc(&mut self, layout: Layout) -> Result<NonNull<u8>, AllocErr>

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

Returns a pointer meeting the size and alignment guarantees of layout.

unsafe fn dealloc(&mut self, ptr: NonNull<u8>, layout: Layout)

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

Deallocate the memory referenced by ptr.

unsafe fn realloc(
    &mut self,
    ptr: NonNull<u8>,
    layout: Layout,
    new_size: usize
) -> Result<NonNull<u8>, AllocErr>

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

Returns a pointer suitable for holding data described by a new layout with layout’s alignment and a size given by new_size. To accomplish this, this may extend or shrink the allocation referenced by ptr to fit the new layout.

unsafe fn alloc_zeroed(
    &mut self,
    layout: Layout
) -> Result<NonNull<u8>, AllocErr>

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

Behaves like alloc, but also ensures that the contents are set to zero before being returned.

fn usable_size(&self, layout: &Layout) -> (usize, usize)

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

Returns bounds on the guaranteed usable size of a successful allocation created with the specified layout.

unsafe fn alloc_excess(&mut self, layout: Layout) -> Result<Excess, AllocErr>

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

Behaves like alloc, but also returns the whole size of the returned block. For some layout inputs, like arrays, this may include extra storage usable for additional data.

unsafe fn realloc_excess(
    &mut self,
    ptr: NonNull<u8>,
    layout: Layout,
    new_size: usize
) -> Result<Excess, AllocErr>

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

Behaves like realloc, but also returns the whole size of the returned block. For some layout inputs, like arrays, this may include extra storage usable for additional data.

unsafe fn grow_in_place(
    &mut self,
    ptr: NonNull<u8>,
    layout: Layout,
    new_size: usize
) -> Result<(), CannotReallocInPlace>

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

Attempts to extend the allocation referenced by ptr to fit new_size.

unsafe fn shrink_in_place(
    &mut self,
    ptr: NonNull<u8>,
    layout: Layout,
    new_size: usize
) -> Result<(), CannotReallocInPlace>

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

Attempts to shrink the allocation referenced by ptr to fit new_size.

fn alloc_one<T>(&mut self) -> Result<NonNull<T>, AllocErr>

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

Allocates a block suitable for holding an instance of T.

unsafe fn dealloc_one<T>(&mut self, ptr: NonNull<T>)

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

Deallocates a block suitable for holding an instance of T.

fn alloc_array<T>(&mut self, n: usize) -> Result<NonNull<T>, AllocErr>

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

Allocates a block suitable for holding n instances of T.

unsafe fn realloc_array<T>(
    &mut self,
    ptr: NonNull<T>,
    n_old: usize,
    n_new: usize
) -> Result<NonNull<T>, AllocErr>

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

Reallocates a block previously suitable for holding n_old instances of T, returning a block suitable for holding n_new instances of T.

unsafe fn dealloc_array<T>(
    &mut self,
    ptr: NonNull<T>,
    n: usize
) -> Result<(), AllocErr>

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

Deallocates a block suitable for holding n instances of T.