alloc::sync::Arc< T > Class Template Reference

A thread-safe reference-counting pointer, analogous to Rust's Arc<T>. More...

Public Member Functions
void	reset ()
	Drops the current allocation, decrementing the strong count.
auto	assume_init ()
	Converts an Arc<MaybeUninit<T>> into an Arc<T> after the value has been initialized.
ref< T >	operator* () noexcept
	Dereferences the Arc, returning a mutable reference to the inner value.
ref< const T >	operator* () const noexcept
	Dereferences the Arc, returning a const reference to the inner value.
T *	operator-> () noexcept
	Provides pointer-like mutable access to the inner value.
T *	operator-> () const noexcept
	Provides pointer-like const access to the inner value.
	operator bool () const noexcept
	Returns true if this Arc is non-empty.
usize	strong_count () const noexcept
	Returns the number of strong (Arc) pointers to the same allocation.
usize	weak_count () const noexcept
	Returns the number of Weak pointers to the same allocation.
Weak< T >	downgrade () const noexcept
	Creates a Weak pointer to the same allocation without incrementing the strong count.
auto	as_ptr () const noexcept
	Returns a raw pointer to the managed value.
auto	get_mut () const noexcept -> Option< mut_ref< T > >
	Returns a mutable reference to the inner value if there are no other Arc or Weak pointers to the same allocation.
auto	try_unwrap () -> Result< T, Arc >
	Attempts to unwrap the Arc, returning the inner value if this is the only strong reference.
auto	into_raw () noexcept
	Consumes the Arc without decrementing the reference count, returning an ArcRaw.

Static Public Member Functions
template<typename... Args>
static auto	make (Args &&... args) -> Arc
	Constructs a new Arc<T>.
static auto	make_uninit () -> Arc< MaybeUninit< T > >
	Creates a new Arc containing an uninitialized value.
static auto	pin (rstd::param_t< T > value) -> Pin< Arc< T > >
	Creates a new Pin<Arc<T>>.
static Arc	from_raw (ArcRaw< T > r) noexcept
	Reconstructs an Arc from an ArcRaw previously obtained via into_raw.
static bool	ptr_eq (const Arc &a, const Arc &b) noexcept
	Returns true if the two Arcs point to the same allocation (not just values that compare as equal).
static bool	is_unique (const Arc &arc) noexcept
	Returns true if this is the only Arc or Weak pointer to the allocation.

Friends
template<typename , typename >
struct	rstd::Impl

Detailed Description

template<typename T>
class alloc::sync::Arc< T >

A thread-safe reference-counting pointer, analogous to Rust's Arc<T>.

Template Parameters

T	The type of the value managed by atomic reference counting.

Member Function Documentation

assume_init()

template<typename T >

auto alloc::sync::Arc< T >::assume_init ( )

inline

Converts an Arc<MaybeUninit<T>> into an Arc<T> after the value has been initialized.

Returns

An Arc<T> over the now-initialized value.

downgrade()

template<class T >

auto alloc::sync::Arc< T >::downgrade ( ) const

noexcept

Creates a Weak pointer to the same allocation without incrementing the strong count.

Returns

A Weak<T> pointer.

from_raw()

template<typename T >

static Arc alloc::sync::Arc< T >::from_raw ( ArcRaw< T > r )

inlinestaticnoexcept

Reconstructs an Arc from an ArcRaw previously obtained via into_raw.

Parameters

r	The raw Arc representation.

Returns

An Arc that takes back ownership.

into_raw()

template<typename T >

auto alloc::sync::Arc< T >::into_raw ( )

inlinenoexcept

Consumes the Arc without decrementing the reference count, returning an ArcRaw.

Returns

An ArcRaw<T> for low-level interop; must be reconverted with from_raw.

make_uninit()

template<typename T >

static auto alloc::sync::Arc< T >::make_uninit ( ) -> Arc<MaybeUninit<T>>

inlinestatic

Creates a new Arc containing an uninitialized value.

The returned Arc contains a MaybeUninit<T> that must be initialized before calling assume_init() to convert to Arc<T>.

Example

auto arc = Arc<int>::make_uninit();
// Initialize the value
Arc::get_mut(arc).unwrap().write(42);
auto initialized = arc.assume_init();

pin()

template<typename T >

static auto alloc::sync::Arc< T >::pin ( rstd::param_t< T > value ) -> Pin<Arc<T>>

inlinestatic

Creates a new Pin<Arc<T>>.

If T does not implement Unpin, then the value will be pinned in memory and unable to be moved.

This is useful for types that must not be moved after creation, such as self-referential structures.

strong_count()

template<typename T >

usize alloc::sync::Arc< T >::strong_count ( ) const

inlinenoexcept

Returns the number of strong (Arc) pointers to the same allocation.

Returns

The current strong reference count.

try_unwrap()

template<typename T >

auto alloc::sync::Arc< T >::try_unwrap ( ) -> Result<T, Arc>

inline

Attempts to unwrap the Arc, returning the inner value if this is the only strong reference.

Returns

Ok(T) if successful, or Err(Arc) if other strong references exist.

weak_count()

template<typename T >

usize alloc::sync::Arc< T >::weak_count ( ) const

inlinenoexcept

Returns the number of Weak pointers to the same allocation.

Returns

The current weak reference count (excluding the implicit weak held by strong pointers).

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The documentation for this class was generated from the following file:

• /home/runner/work/rstd/rstd/src/alloc/sync.cppm