boost::capy::neunique_ptr

A smart pointer with unique ownership, type‐erased deleter, and allocator support.

Synopsis

Declared in <boost/capy/neunique_ptr.hpp>

template<class T>
class neunique_ptr;

Description

This class provides unique ownership semantics similar to std::unique_ptr, combined with features from std::shared_ptr:

Type‐erased deleters ‐ pointers with different deleters share the same static type
Allocator support ‐ custom allocators for the control block
Incomplete types ‐ the destructor is captured at construction
Aliasing ‐ the stored pointer can differ from the owned pointer

The implementation uses a control block to store the deleter and allocator, similar to std::shared_ptr but without reference counting.

Control Block Elision

When constructed from a raw pointer without a custom deleter or allocator, no control block is allocated. The pointer is deleted directly using delete. This optimization requires the type to be complete at destruction time.

Size

sizeof(neunique_ptr<T>) is two pointers (16 bytes on 64‐bit).

Thread Safety

Distinct neunique_ptr objects may be accessed concurrently. A single neunique_ptr object may not be accessed concurrently from multiple threads.

Types

Name

Description

The element type.

The pointer type.

Member Functions

Name

Description

neunique_ptr [constructor]

Constructors

~neunique_ptr [destructor]

Destructor.

operator= [deleted]

Assignment operators

Return the stored pointer.

Dereference the pointer.

Member access.

reset overloads

Swap with another pointer.

operator bool

Check if non‐empty.

Friends

Name Description

boost::capy::allocate_neunique

boost::capy::neunique_ptr

A smart pointer with unique ownership, type‐erased deleter, and allocator support.

Non-Member Functions

Name

Description

allocate_neunique

Create a neunique_ptr using a custom allocator.

allocate_neunique

Create a neunique_ptr for an array using a custom allocator.

make_neunique

Create a neunique_ptr for a single object.

make_neunique

Create a neunique_ptr for an array.

Compare with nullptr.

Compare for inequality.

Less‐than comparison with nullptr.

Less‐than comparison.

Less‐than‐or‐equal comparison with nullptr.

Less‐than‐or‐equal comparison.

Compare for equality.

Compare with nullptr.

Greater‐than comparison with nullptr.

Greater‐than comparison.

Greater‐than‐or‐equal comparison with nullptr.

Greater‐than‐or‐equal comparison.

Swap two pointers.

Template Parameters

Name	Description
T	The element type. May be incomplete at declaration. For arrays, use `neunique_ptr<T[]>`.

See Also

make_neunique, allocate_neunique

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