boost::openmethod::virtual_ptr

Wide pointer combining pointers to an object and its v‐table

Synopsis

Declared in <boost/openmethod/core.hpp>

template<
    class Class,
    class Registry = boost::openmethod::default_registry,
    typename = /* implementation-defined */>
class virtual_ptr;

Description

A virtual_ptr is a wide pointer that combines pointers to an object and its v‐table. Calls to methods via virtual_ptr are as fast as ordinary virtual function calls (typically two instructions).

A virtual_ptr can be implicitly constructed from a reference, a pointer, or another virtual_ptr, provided that they are type‐compatible.

virtual_ptr has specializations that use a std::shared_ptr or a std::unique_ptr as the pointer to the object. The mechanism can be extended to other smart pointers by specializing virtual_traits. A "plain" virtual_ptr can be constructed from a smart virtual_ptr, but not the other way around.

The default value for Registry can be customized by defining the BOOST_OPENMETHOD_DEFAULT_REGISTRY preprocessor symbol.

Requirements

  • virtual_traits must be specialized for `Class&`.

  • `Class` must be a class type, possibly cv‐qualified, registered in `Registry`.

Types

Name

Description

element_type

Class

Member Functions

Name

Description

virtual_ptr [constructor]

Constructors

operator=

Assignment operators

get

Get a pointer to the object

operator‐>

Get a pointer to the object

operator*

Get a reference to the object

pointer

Get a pointer to the object

cast

Cast to another virtual_ptr type

vptr

Get the v‐table pointer

Static Member Functions

Name

Description

final

Construct a virtual_ptr from a reference to an object

Non-Member Functions

Name

Description

operator!=

Compare two `virtual_ptr`s for inequality.

operator==

Compare two `virtual_ptr`s for equality.

Template Parameters

Name Description

Class

The class of the object, possibly cv‐qualified

Registry

The registry in which Class is registered

unnamed

Implementation defined, use default

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